Go Math Grade 8 Answer Key Chapter 6 Functions

Go Math Grade 8 Answer Key Chapter 6 Functions PDF is provided here for download. The best-loved math experts are provided an easy way of solving maths questions along with the explanations. Every problem is simplified with a clear explanation with many tricks. Great problems with a high level of difficulty also solved in an easy way. Refer to Go Math Grade 8 Answer Key Chapter 6 Functions now to begin your practice.

Go Math Grade 8 Chapter 6 Functions Answer Key

Prefer learning using Go Math Grade 8 Chapter 6 Functions Solution Key. To get the good results in an exam you must prepare with the Go Math Grade 8 Chapter 6 Answer Key. Use HMH Go Math Grade 8 Answer Key for the best practice of maths. Step by step explanation is provided for every question below. Build your confidence in solving math problems by practicing with Go Math Grade 8 Answer Key Chapter 6 Functions.

Lesson 1: Identifying and Representing Functions 

Lesson 2: Describing Functions

Lesson 3: Comparing Functions 

Lesson 4: Analyzing Graphs

Lesson 5: Model Quiz 

Lesson 6: Mixed Review 

Guided Practice – Identifying and Representing Functions – Page No. 158

Complete each table. In the row with x as the input, write a rule as an algebraic expression for the output. Then complete the last row of the table using the rule.

Question 1.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 1: Identifying and Representing Functions img 1
Type below:
_______________

Answer:
Grade 8 Chapter 6 image 1

Explanation:
Unit Cost of ticket = 40/2 = 20
Total cost = 20x where x is the number of tickets.
x = 20x
10 = 20(100) = 200

Question 2.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 1: Identifying and Representing Functions img 2
Type below:
_______________

Answer:
Grade 8 Chapter 6 image 2

Explanation:
Number of pages per minute = 1/2 = 0.5
Total cost = 0.5x where x is the number of minutes.
x = 0.5x
30 = 0.5(30) = 15

Question 3.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 1: Identifying and Representing Functions img 3
Type below:
_______________

Answer:
Grade 8 Chapter 6 image 3

Explanation:
Units cost of Muffins = 2.25/1 = 2.25
Total cost = 2.25x where x is the number of muffins
x = 2.25x
12 = 2.25(12) = 27

Determine whether each relationship is a function.

Question 4.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 1: Identifying and Representing Functions img 4
_______________

Answer:
Function

Explanation:
Each input is assigned to exactly one output.

Question 5.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 1: Identifying and Representing Functions img 5
_______________

Answer:
Not a function

Explanation:
The input value is 4 is paired with two outputs 25 and 35

Question 6.
The graph shows the relationship between the weights of 5 packages and the shipping charge for each package. Is the relationship represented by the graph a function? Explain.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 1: Identifying and Representing Functions img 6
_______________

Answer:
Function

Explanation:
Each input is assigned to exactly one output.

Essential Question Check-In

Question 7.
What are four different ways of representing functions? How can you tell if a relationship is a function?
Type below:
_______________

Answer:
The function can be represented by an equation, table, graph, and Venn diagram.
If a relationship is a function, each input is paired with exactly one output.

Independent Practice – Identifying and Representing Functions – Page No. 159

Determine whether each relationship represented by the ordered pairs is a function. Explain.

Question 8.
(2, 2), (3, 1), (5, 7), (8, 0), (9, 1)
_______________

Answer:
Function

Explanation:
Each input value is paired with exactly one output value.

Question 9.
(0, 4), (5, 1), (2, 8), (6, 3), (5, 9)
_______________

Answer:
Not a function

Explanation:
The input value is 5 is paired with two outputs 1 and 9

Question 10.
Draw Conclusions
Joaquin receives $0.40 per pound for 1 to 99 pounds of aluminum cans he recycles. He receives $0.50 per pound if he recycles more than 100 pounds. Is the amount of money Joaquin receives a function of the weight of the cans he recycles? Explain your reasoning.
_______________

Answer:
Yes

Explanation:
The amount of money increases with the weight of the cans. No weight will result in the same amount of money earned.

Question 11.
A biologist tracked the growth of a strain of bacteria, as shown in the graph.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 1: Identifying and Representing Functions img 7
a. Explain why the relationship represented by the graph is a function.
Type below:
_______________

Answer:
The relationship is a function as each input has been assigned exactly one output. There is only one number of bacteria for each number of hours.

Question 11.
b. What If?
Suppose there was the same number of bacteria for two consecutive hours. Would the graph still represent a function? Explain.
Type below:
_______________

Answer:
Yes. If the number of bacteria for two consecutive hours is the same, one input will still be paired with one output, hence the relationship is still a function.

Question 12.
Multiple Representations
Give an example of a function in everyday life, and represent it as a graph, a table, and a set of ordered pairs. Describe how you know it is a function.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 1: Identifying and Representing Functions img 8
Type below:
_______________

Answer:
The cost of a bouquet of flowers and the number of flowers in the bouquet is a function. The unit cost of flowers = $0.85 and x the number of flowers. Hence, C= 0.85x
Grade 8 Chapter 6 image 4
Grade 8 Chapter 6 image 5
(2, 1.7), (4, 3.4), (6, 5.1), (8, 6.8), (10, 8.5)
Each value of the input is paired with exactly one output.

Identifying and Representing Functions – Page No. 160

The graph shows the relationship between the weights of six wedges of cheese and the price of each wedge.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 1: Identifying and Representing Functions img 9

Question 13.
Is the relationship represented by the graph a function? Justify your reasoning. Use the words “input” and “output” in your explanation, and connect them to the context represented by the graph.
_______________

Answer:
Yes, the relationship represented by the graph is a function.
Each input (weight) in the graph is paired with exactly one output(price).

Question 14.
Analyze Relationships
Suppose the weights and prices of additional wedges of cheese were plotted on the graph. Might that change your answer to question 13? Explain your reasoning.
Type below:
_______________

Answer:
No. As the weight of the cheese will increase, the cost of wedges of cheese will increase as well. Hence, for each input (weight), there would be exactly one output (price).

H.O.T.

Focus on Higher Order Thinking

Question 15.
Justify Reasoning
A mapping diagram represents a relationship that contains three different input values and four different output values. Is the relationship a function? Explain your reasoning.
_______________

Answer:
No. Since there are three inputs and four outputs, one of the inputs will have more than one output, hence the relationship cannot be a function.

Question 16.
Communicate Mathematical Ideas
An onion farmer is hiring workers to help harvest the onions. He knows that the number of days it will take to harvest the onions is a function of the number of workers he hires. Explain the use of the word “function” in this context.
Type below:
_______________

Answer:
Number of days = f(number of workers)

Explanation:
We know that the more the number of workers will be involved in the harvesting of onion, the lesser days it will take to complete.
Thus the number of workers becomes the independent variable and the number of days becomes the dependent variable.
Here the word function is used to describe that the number of days is dependent on the number of workers.
Number of days = f(number of workers)

Guided Practice – Describing Functions – Page No. 164

Plot the ordered pairs from the table. Then graph the function represented by the ordered pairs and tell whether the function is linear or nonlinear.

Question 1.
y = 5 − 2x
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 2: Describing Functions img 10
_______________

Answer:
Grade 8 Chapter 6 image 6
Grade 8 Chapter 6 image 7
Graph of a linear function is a straight line
Linear relationship

Explanation:
Given y = 5 – 2x
y = 5 – 2(-1) = 5 + 2 = 7
y = 5 – 2(1) = 5 – 2 = 3
y = 5 – 2(3) = 5 – 6 = -1
y = 5 – 2(5) = 5 – 10 = -5

Question 2.
y = 2 − x2
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 2: Describing Functions img 11
_______________

Answer:
y = 2 − x2
Grade 8 Chapter 6 image 8
Graph the ordered pairs. Then draw a line through the points to represent the solution.
Grade 8 Chapter 6 image 9
Graph of a linear function is not a straight line
Non-linear relationship

Explanation:
y = 2 − x2
y = 2 – 4 = -2
y = 2 – 1 = 1
y = 2 – 0 = 2
y = 2 – 1 = 1
y = 2 – 4 = -2

Explain whether each equation is a linear equation.

Question 3.
y = x2 – 1
_______________

Answer:
The equation is not in the form of a linear equation, hence is not a linear equation.

Explanation:
Compare the equation with the general linear equation y = mx + b.
The equation is not in the form of a linear equation, hence is not a linear equation.

Question 4.
y = 1 – x
_______________

Answer:
The equation is in the form of a linear equation, hence is a linear equation.

Explanation:
Compare the equation with the general linear equation y = mx + b.
The equation is in the form of a linear equation, hence is a linear equation.

Essential Question Check-In

Question 5.
Explain how you can use a table of values, an equation, and a graph to determine whether a function represents a proportional relationship.
Type below:
_______________

Answer:
From a table, determine the ratio y/x. If it is constant the relationship is proportional.
From a graph, note if the graph passes through the origin. The graph of a proportional relationship must pass through the origin (0, 0).
From an equation, compare with general linear form of equation, y = mx + b. If b = 0, the relationship is proportional.

Independent Practice – Describing Functions – Page No. 165

Question 6.
State whether the relationship between x and y in y = 4x – 5 is proportional or nonproportional. Then graph the function.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 2: Describing Functions img 12
_______________

Answer:
Grade 8 Chapter 6 image 10

Explanation:
First, we compare the equation with the general linear equation y = mx + b. y = 4x – 5 is in the form of y = mx + b, with m = 4 and b = -5. Therefore, the equation is a linear equation. Since b is not equal to 0, the relationship is non-proportional.
Then, we choose several values for the input x. We substitute these values of x in the equation to find the output y.
y = 4x – 5
If x = 0; y = 4(0) – 5 = -5; (0, -5)
If x = 2; y = 4(2) – 5 = 3; (2, 3)
If x = 4; y = 4(4) – 5 = 11; (4, 11)
If x = 6; y = 4(6) – 5 = 19; (6, 19)
We graph the ordered pairs and we draw a line through the points to represent the solutions of the function.

Question 7.
The Fortaleza telescope in Brazil is a radio telescope. Its shape can be approximated with the equation y = 0.013x2. Is the relationship between x and y linear? Is it proportional? Explain.
____________
____________

Answer:
Compare the equation with the general linear equation y = mx + b.
The equation is not in the form of a linear equation, hence it is not a linear equation. Since x is squared, it is not proportional.

Question 8.
Kiley spent $20 on rides and snacks at the state fair. If x is the amount she spent on rides, and y is the amount she spent on snacks, the total amount she spent can be represented by the equation x + y = 20. Is the relationship between x and y linear? Is it proportional? Explain.
____________
____________

Answer:
x + y = 20
Rewriting the equation
y = 20 – x
Compare the equation with the general linear equation y = mx + b.
It is linear
Since b is not equal to 0, the relationship is not proportional.

Question 9.
Represent Real-World Problems
The drill team is buying new uniforms. The table shows y, the total cost in dollars, and x, the number of uniforms purchased.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 2: Describing Functions img 13
a. Use the data to draw a graph. Is the relationship between x and y linear? Explain.
____________

Answer:
Grade 8 Chapter 6 image 10
The graph of a linear relationship is a straight line.
x and y are linear.

Question 9.
b. Use your graph to predict the cost of purchasing 12 uniforms.
$ ________

Answer:
$720

Explanation:
Grade 8 Chapter 6 image 10
The cost of 12 uniforms is $720

Question 10.
Marta, a whale calf in an aquarium, is fed a special milk formula. Her handler uses a graph to track the number of gallons of formula y the calf drinks in x hours. Is the relationship between x and y linear? Is it proportional? Explain.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 2: Describing Functions img 14
____________
____________

Answer:
The relationship is linear
The relationship is proportional

Explanation:
As the data lies on a straight line, the relationship is linear
As the graph passes through the origin, the relationship is proportional

Describing Functions – Page No. 166

Question 11.
Critique Reasoning
A student claims that the equation y = 7 is not a linear equation because it does not have the form y=mx + b. Do you agree or disagree? Why?
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 2: Describing Functions img 15
____________

Answer:
Disagree; The equation can be written in the form y = mx + b Where m is 0. The graph of the solutions is a horizontal line.

Question 12.
Make a Prediction
Let x represent the number of hours you read a book and y represent the total number of pages you have read. You have already read 70 pages and can read 30 pages per hour. Write an equation relating x hours and y pages you read. Then predict the total number of pages you will have read after another 3 hours.
_______ pages

Answer:
160 pages

Explanation:
Let x represent the number of hours you read a book and y represents the total number of pages you have read. You have already read 70 pages and can read 30 pages per hour.
m = 30; b = 70 pages
y = 30x + 70
x = 3 hrs
y = 30(3) + 70 = 160

H.O.T.

Focus on Higher Order Thinking

Question 13.
Draw Conclusions
Rebecca draws a graph of a real-world relationship that turns out to be a set of unconnected points. Can the relationship be linear? Can it be proportional? Explain your reasoning.
Type below:
______________

Answer:
The relationship is linear if all the points lie on the same line. If the relationship is linear and passes through the origin, it is proportional.

Question 14.
Communicate Mathematical Ideas
Write a real-world problem involving a proportional relationship. Explain how you know the relationship is proportional.
Type below:
______________

Answer:
The amount of money earned at a car wash is a proportional relationship. When there are 0 cars washed, $0 are earned. The amount of money earned increases by the unit cost of a car wash.

Question 15.
Justify Reasoning
Show that the equation y + 3 = 3(2x + 1) is linear and that it represents a proportional relationship between x and y.
Type below:
______________

Answer:
y + 3 = 3(2x + 1)
y +3 = 6x + 3
y = 6x
As b = 0, it is a Proportional Relationship.

Guided Practice – Comparing Functions – Page No. 170

Doctors have two methods of calculating maximum heart rate. With the first method, maximum heart rate, y, in beats per minute is y = 220 − x, where x is the person’s age. Maximum heart rate with the second method is shown in the table.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 3: Comparing Functions img 16

Question 1.
Which method gives the greater maximum heart rate for a 70-year-old?
____________ method

Answer:
Second

Explanation:
y = 220 – x
y = 220 – 70 = 150
Find the slope using two points from the grapgh by
Slope m = (y2 -y1)/(x2 – x1) where (x1, y1) = (20, 194) and (x2, y2) = (30, 187)
Slope m = (y2 -y1)/(x2 – x1) = (187 – 194)/(30 – 20) = -7/10 = -0.7
197 = -0.7(20) + b
y-intercept b = 208
Substituting the value of the slope m and y-intercept in the slope-intercept form. y = mx + b where, m = -0.7 and b = 208.
y = -0.7x +208
x = 70yrs
y = -0.7(70) + 208 = 159
150 < 159
Second method gives the greater maximum heart rate for a 70 year ols.

Question 2.
Are heart rate and age proportional or nonproportional for each method?
____________

Answer:
For method 1, the relationship is non-propotional.
For method 2, the relationship is non-propotional.

Explanation:
Compare the equation with the general linear equation y = mx + b.
It is linear
Since b is not equal to 0, the relationship is not proportional.

Aisha runs a tutoring business. With Plan 1, students may choose to pay $15 per hour. With Plan 2, they may follow the plan shown on the graph.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 3: Comparing Functions img 17

Question 3.
Describe the plan shown on the graph.
Type below:
______________

Answer:
Choose two points on the graph to find the slope.
Find the slope
m = (y2 -y1)/(x2 – x1)
m = (60 – 40)/(4 – 0) = 20/4 = 5
Read the y-intercept from the graph: b = 40
Use your slope and y-intercept values to write an equation in slope-intercept
form.
y = 5x + 40
Plan 2 has an intial cost of $40 and a rate of $5 per hour.

Question 4.
Sketch a graph showing the $15 per hour option.
Type below:
______________

Answer:
Grade 8 Chapter 6 image 11

Question 5.
What does the intersection of the two graphs mean?
Type below:
______________

Answer:
The intersection of the two graphs represents the number of hours for which both plans will cost the same,

Question 6.
Which plan is cheaper for 10 hours of tutoring?
______________

Answer:
Plan 1
y = 15x
x = 10 hrs
y = 15(10) = $150
Plan 2
y = 5x + 40
y = 5(10) + 40 = $90
$150 > $90
Plane 2 is cheaper

Question 7.
Are cost and time proportional or nonproportional for each plan?
Type below:
______________

Answer:
Comparing with the general linear form of equation y = mx + b. Since b = 0, the relationship is proportional
The cost and time are proportional for Plan 1
Comparing with the general linear form of equation y = mx + b. Since b is not equal to 0, the relationship is proportional
The cost and time are not proportional for Plan 2

Essential Question Check-In

Question 8.
When using tables, graphs, and equations to compare functions, why do you find the equations for tables and graphs?
Type below:
______________

Answer:
The tables and graphs represent a part of the solution of the function. By writing the equation, any value can be a substitute to evaluate the function and compared it with the equations.

Independent Practice – Comparing Functions – Page No. 171

The table and graph show the miles driven and gas used for two scooters.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 3: Comparing Functions img 18

Question 9.
Which scooter uses fewer gallons of gas when 1350 miles are driven?
______________

Answer:
Scooter B uses fewer gallons of gas when 1350 miles are driven

Explanation:
The equation for Scooter A Slope m = m = (y2 -y1)/(x2 – x1) where (x1, y1) = (150, 2) and (x2, y2) = (300, 4)
Slope m = (y2 -y1)/(x2 – x1) = (4 – 2)/(300 – 150) = 2/150 = 1/75
2 = 1/75(150) + b
y-intercept b = 0
Substituting the value of the slope m and y-intercept in the slope-intercept form. y = mx + b where, m = 1/75 and b = 0.
y = 1/75x
x = 1350 miles
y = 1/75(1,350)
y = 18gal
The equation for Scooter B Slope m = m = (y2 -y1)/(x2 – x1) where (x1, y1) = (0, 0) and (x2, y2) = (90, 1)
Slope m = (y2 -y1)/(x2 – x1) = (1 – 0)/(90 – 0) = 1/90
2 = 1/90(90) + b
y-intercept b = 0
Substituting the value of the slope m and y-intercept in the slope-intercept form. y = mx + b where, m = 1/90 and b = 0.
y = 1/90x
x = 1350 miles
y = 1/90(1,350)
y = 15gal
Compare the gallons of gas to drive 1,350 miles
18 > 15
Scooter B uses fewer gallons of gas when 1,350 miles are driven.

Question 10.
Are gas used and miles proportional or nonproportional for each scooter?
______________

Answer:
The gas used and miles are proportional to both scooters.

Explanation:
Compare with general linear form of an equation, y = mx + b. If b = 0, the relationship is proportional.
The gas used and miles are proportional to both scooters.

A cell phone company offers two texting plans to its customers. The monthly cost, y dollars, of one plan is y = 0.10x + 5, where x is the number of texts. The cost of the other plan is shown in the table.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 3: Comparing Functions img 19

Question 11.
Which plan is cheaper for under 200 texts?
______________

Answer:
Plane 1 is cheaper

Explanation:
Plan 1
y = 0.10x + 5
Subsitute x = 199
y = 0.10(199) + 5 = $24.90
Find the slope using two points from the graph by m = (y2 -y1)/(x2 – x1) where (x1, y1) = (100, 20), (x2, y2) =(200, 25)
Substitute the value of m and (x1, y1) = (100, 20), (x2, y2) =(200, 25)
Slope m = (y2 -y1)/(x2 – x1) = (25 – 20)/(200 – 100) = 5/100 = 0.05
20 = 0.05(100) + b
y-intercept b = 15
Substituting the value of slope (m) and (x, y) in the slope intercept form to find y intercept (b):
y = 0.05x + 15
x = 199
y = 0.05(199) + 15 = $24.95
Compare the cost for two plans for text < 200
$24.90 < $24.95
Plane 1 is cheaper

Question 12.
The graph of the first plan does not pass through the origin. What does this indicate?
Type below:
______________

Answer:
Plan 1
y = 0.10x + 5
The graph that does not pass through the origin indicates that there is a base price of $5 for the plan.

Question 13.
Brianna wants to buy a digital camera for a photography class. One store offers the camera for $50 down and a payment plan of $20 per month. The payment plan for a second store is described by y = 15x + 80, where y is the total cost in dollars and x is the number of months. Which camera is cheaper when the camera is paid off in 12 months? Explain.
______________

Answer:
For first store, the slope interecept form y = mx + b where m = 20 dollars per month and b = 50 dollar.
y = 20x + 50
x = 12 months
y = 20(12) + 50 = $290
Second store
y = 15x + 80
x = 12 months
y = 15(12) + 80 = $260
Compare the cost of camera if it paid off in 12 months $290 > $260
Camera is cheaper at second store

Comparing Functions – Page No. 172

Question 14.
The French club and soccer team are washing cars to earn money. The amount earned, y dollars, for washing x cars is a linear function. Which group makes the most money per car? Explain.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 3: Comparing Functions img 20
______________

Answer:

Explanation:
Find the slope using two points from the grapgh by
Slope m = (y2 -y1)/(x2 – x1) where (x1, y1) = (2, 10) and (x2, y2) = (4, 20)
Slope m = (y2 -y1)/(x2 – x1) = (20 – 10)/(4 – 2) = 10/2 = 5
French Club makes $5 per car.
Find the slope using two points from the grapgh by
Slope m = (y2 -y1)/(x2 – x1) where (x1, y1) = (0, 0) and (x2, y2) = (2, 16)
Slope m = (y2 -y1)/(x2 – x1) = (16 – 0)/(2 – 0) = 16/2 = 8
Soccer Club makes $8 per car.
Compare the money earned for washing one car $5 < $8
Soccer club makes the most money per car

H.O.T.

Focus on Higher Order Thinking

Question 15.
Draw Conclusions
Gym A charges $60 a month plus $5 per visit. The monthly cost at Gym B is represented by y = 5x + 40, where x is the number of visits per month. What conclusion can you draw about the monthly costs of the gyms?
__________ is more expensive

Answer:
Gym A is more expensive

Explanation:
Since the rate per visit is the same, the monthly cost of Gyn A is always more than Gym B.

Question 16.
Justify Reasoning
Why will the value of y for the function y = 5x + 1 always be greater than that for the function y = 4x + 2 when x > 1?
Type below:
______________

Answer:
y1 = 5x + 1 and y2 = 4x + 2 Subtracting y2 from y1
y1 – y2 = 5x + 1 – (4x + 2)
y1 – y2 = x -1
For x>= 1 we get x – 1 >= 0
So y1 – y2 >= 0 or y1 >= y2

Question 17.
Analyze Relationships
The equations of two functions are y = −21x + 9 and y = −24x + 8. Which function is changing more quickly? Explain.
______________

Answer:
y = -21x + 9
y = -24x + 8
y = -24x + 8 is changing more quickly as the absolute value of -24 is greater than the absolute value of -21.

Guided Practice – Analyzing Graphs – Page No. 176

In a lab environment, colonies of bacteria follow a predictable pattern of growth. The graph shows this growth over time.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 4: Analyzing Graphs img 21

Question 1.
What is happening to the population during Phase 2?
______________

Answer:
For Phase 2, the graph is increasing quickly. This shows a period of rapid growth.

Question 2.
What is happening to the population during Phase 4?
______________

Answer:
In Phase 4, the graph is decreasing, hence the number of bacterias is decreasing.

The graphs give the speeds of three people who are riding snowmobiles. Tell which graph corresponds to each situation.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 4: Analyzing Graphs img 22

Question 3.
Chip begins his ride slowly but then stops to talk with some friends. After a few minutes, he continues his ride, gradually increasing his speed.
______________

Answer:
Graph 2

Explanation:
The slope of the graph is increasing, then it becomes constant and starts increasing again.
Graph 2

Question 4.
Linda steadily increases her speed through most of her ride. Then she slows down as she nears some trees.
______________

Answer:
Graph 3

Explanation:
The slope of the graph is increasing and then decreasing.
Graph 3

Question 5.
Paulo stood at the top of a diving board. He walked to the end of the board, and then dove forward into the water. He plunged down below the surface, then swam straight forward while underwater. Finally, he swam forward and upward to the surface of the water. Draw a graph to represent Paulo’s elevation at different distances from the edge of the pool.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 4: Analyzing Graphs img 23
Type below:
______________

Answer:
Grade 8 Chapter 6 image 12

Independent Practice – Analyzing Graphs – Page No. 177

Tell which graph corresponds to each situation below.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 4: Analyzing Graphs img 24

Question 6.
Arnold started from home and walked to a friend’s house. He stayed with his friend for a while and then walked to another friend’s house farther from home.
______________

Answer:
Graph 3

Explanation:
The graph increases (as Arnold walks from home to friend’s house), then becomes constant (when he stayed with his friend) and then increases again (when he walk to another friend’s house farther away).
Graph 3

Question 7.
Francisco started from home and walked to the store. After shopping, he walked back home.
______________

Answer:
Graph 1

Explanation:
The graph increases (as Francisco walked from home to store), becomes constant (when he shops), and then decreases (as he walked back home)
Graph 1

Question 8.
Celia walks to the library at a steady pace without stopping.
______________

Answer:
Graph 2

Explanation:
The graph increases at a constant rate (as Celia walks to library without any stops)
Graph 2

Regina rented a motor scooter. The graph shows how far away she is from the rental site after each half hour of riding.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 4: Analyzing Graphs img 25

Question 9.
Represent Real-World Problems
Use the graph to describe Regina’s trip. You can start the description like this: “Regina left the rental shop and rode for an hour…”
Type below:
______________

Answer:
Regina left the rental shop and rode for an hour. She rested for half an hour and then started back. After half an hour, she changed her mind and rode for another half an hour. She rest for half an hour. Then she started back and ranched the rental site in 2 hours.

Question 10.
Analyze Relationships
Determine during which half hour Regina covered the greatest distance.
Type below:
______________

Answer:
Regina covered the greatest distance between 0.5 to 1hr of the journey. She covered 12 miles.

Analyzing Graphs – Page No. 178

The data in the table shows the speed of a ride at an amusement park at different times one afternoon.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 4: Analyzing Graphs img 26

Question 11.
Sketch a graph that shows the speed of the ride over time.
Type below:
______________

Answer:
Grade 8 Chapter 6 image 13

Question 12.
Between which times is the ride’s speed increasing the fastest?
Type below:
______________

Answer:
The speed is increasing the fastest during the 3: 21 and 3: 22

Question 13.
Between which times is the ride’s speed decreasing the fastest?
Type below:
______________

Answer:
The speed is decreasing the fastest during the 3: 23 and 3: 24

H.O.T.

Focus on Higher Order Thinking
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 4: Analyzing Graphs img 27

Question 14.
Justify Reasoning
What is happening to the fox population before time t? Explain your reasoning.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 4: Analyzing Graphs img 28
Type below:
______________

Answer:
The population decreases and then increases before time t

Question 15.
What If?
Suppose at time t, a conservation organization moves a large group of foxes to the island. Sketch a graph to show how this action might affect the population on the island after time t.
Go Math Grade 8 Answer Key Chapter 6 Functions Lesson 4: Analyzing Graphs img 29
Type below:
______________

Answer:
Grade 8 Chapter 6 image 14

Explanation:
Population is decreasing at first, then it is increasing rapidly.

Question 16.
Make a Prediction
At some point after time t, a forest fire destroys part of the woodland area on the island. Describe how your graph from problem 15 might change.
Type below:
______________

Answer:
The population would dramatically decrease if there was a fire due to lack of food supply and good land.

6.1 Identifying and Representing Functions – Model Quiz – Page No. 179

Determine whether each relationship is a function.

Question 1.
Go Math Grade 8 Answer Key Chapter 6 Functions Model Quiz img 30
__________

Answer:
Not a function

Explanation:
A relationship is a function when each input is paired with exactly one output. The input 5 has more than one output.
Not a function

Question 2.
Go Math Grade 8 Answer Key Chapter 6 Functions Model Quiz img 31
__________

Answer:
Function

Explanation:
A relationship is a function when each input is paired with exactly one output.
Each input is paired with only one output.
Function

Question 3.
(2, 5), (7, 2), (−3, 4), (2, 9), (1, 1)
__________

Answer:
Not a function

Explanation:
A relationship is a function when each input is paired with exactly one output. Input 2 has more than one output.
Not a function

6.2 Describing Functions

Determine whether each situation is linear or nonlinear, and proportional or nonproportional.

Question 4.
Joanna is paid $14 per hour.
__________
__________

Answer:
Linear
Proportional

Explanation:
Writing the situation as an equation, where x is the number of hours.
y = 14x
Compare with general linear equation y = mx + b
Linear
Since b = 0, the relationship is proportional.
Proportional

Question 5.
Alberto started out bench pressing 50 pounds. He then added 5 pounds every week.
__________
__________

Answer:
Linear
Non-proportional

Explanation:
Writing the situation as an equation, where x is the number of hours.
y = 5x + 50
Compare with general linear equation y = mx + b
Linear
Since b is not equal to 0, the relationship is non-proportional.
Non-proportional

6.3 Comparing Functions

Question 6.
Which function is changing more quickly? Explain.
Go Math Grade 8 Answer Key Chapter 6 Functions Model Quiz img 32
__________

Answer:
Function 2 is changing more quickly.

Explanation:
Find the rate of change for function 1
Rate of Change = (20 – 0)/(0 – 5) = -4
Find the rate of change for function 1
Rate of Change = (6.5 – 11)/(3 – 2) = -4.5
Althogh -4.5 < -4, the absolute value of -4.5 s greater than -4.
Function 2 is changing more quickly.

6.4 Analyzing Graphs

Question 7.
Describe a graph that shows Sam running at a constant rate.
Type below:
______________

Answer:
The graph would be a straight line

Explanation:
Since Sam is running at a constant rate, distance covered per unit of time remains the same and the relationship is linear and proportional.
The graph would be a straight line

Essential Question

Question 8.
How can you use functions to solve real-world problems?
Type below:
______________

Answer:
If in the equation the power of x is 1 then it is linear otherwise nonlinear.
In a graph, if the points form a line it is linear if they form a curve it is a nonlinear function.

Selected Response – Mixed Review – Page No. 180

Question 1.
Which table shows a proportional function?
Go Math Grade 8 Answer Key Chapter 6 Functions Mixed Review img 33
Options:
a. A
b. B
c. C
d. D

Answer:
c. C

Explanation:
It contains the ordered pair of the origin (0, 0)
Option C represents a proportional relationship.

Question 2.
What is the slope and y-intercept of the function shown in the table?
Go Math Grade 8 Answer Key Chapter 6 Functions Mixed Review img 34
Options:
a. m = -2; b = -4
b. m = -2; b = 4
c. m = 2; b = 4
d. m = 4; b = 2

Answer:
c. m = 2; b = 4

Explanation:
Find the slope using two points from the grapgh by
Slope m = (y2 -y1)/(x2 – x1) where (x1, y1) = (1, 6) and (x2, y2) = (4, 12)
Slope m = (y2 -y1)/(x2 – x1) = (12 – 6)/(4 – 1) = 6/3 = 2
Substituting the value of the slope m and (x, y) to find the slope-intercept form.
12 = 4(2) + b
y-intercept b = 4

Question 3.
The table below shows some input and output values of a function.
Go Math Grade 8 Answer Key Chapter 6 Functions Mixed Review img 35
What is the missing output value?
Options:
a. 20
b. 21
c. 22
d. 23

Answer:
b. 21

Explanation:
Find the rate of change = (17.5 – 14)/(5 – 4) = 3.5
Since the missing output is corresponding to x = 6 and 3.5 to 17.5 (for x = 5)
Output = 17.5 + 3.5 = 21

Question 4.
Tom walked to school at a steady pace, met his sister, and they walked home at a steady pace. Describe this graph.
Options:
a. V-shaped
b. upside down V-shaped
c. Straight line sloping up
d. Straight line sloping down

Answer:
b. upside-down V-shaped

Explanation:
The graph would increase at a constant rate and would decrease at a constant rate.
The graph would be the upside-down V-shaped

Mini-Task

Question 5.
Linear functions can be used to find the price of a building based on its floor area.Below are two of these functions.
y = 40x + 15,000
Go Math Grade 8 Answer Key Chapter 6 Functions Mixed Review img 36
a. Find and compare the slopes.
Type below:
____________

Answer:
Compare the slopes
The slope for the first function is less than the slope of the second function.
y = 40x + 15000
Compare with slope intercept form y = mx + b where m is the slope m = 40
Second function find the slope using given points by Slope m = (y2 -y1)/(x2 – x1) where (x1, y1) = (7, 3) and (x2, y2) = (6, 4)
Slope m = (y2 -y1)/(x2 – x1) = (56000 – 32000)/(700 – 400) = 24000/300 = 80
m = 80

Question 5.
b. Find and compare the y-intercepts.
Type below:
____________

Answer:
y = 40x + 15,000
Compare with slope-intercept form y = mx + b where m is the slope b = 15000
The second function find the slope using given points by Slope m and (x, y) in the slope-intercept form to fins y-intercept b
y = mx + b where (x, y) = (700, 56000) and m = 80
56000 = 80(700) + b
b = 0
Compare y intercepts
The y-intercept of the first function is greater than the y-intercept of the second function

Question 5.
c. Describe each function as proportional or nonproportional.
Type below:
____________

Answer:
Comparable to slope interecept form y = mx + b
First function: y = 40x + 15000
Second function: y = 80x
Since b is not equal to 0
First function is non-proportional
Since b = 0
The second function is proportional.

Conclusion:

Download Go Math Grade 8 Answer Key Chapter 6 Functions PDF for free. The famous and great math experts are worked to provide the best way of solving math problems. Immediately, start your practice and learn maths easily.

Leave a Comment