Over Chapter 7

A. A

B. B

C. C

D. D A B C D

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A. 26

B. 52

C. 78

D. 156

The circle graph shows the results of a middle school survey about favorite lunch foods. Suppose 650 students were surveyed. How many more students favor salad than hoagies?

You have already learned how to find function rules and create function tables. (Lesson 1–5)

• Determine whether a relation is a function.

• Write a function using function notation.

• independent variable

• dependent variable

• vertical line test

• function notation

The variable in a function with a value that is subject to choice (you pick it)

The variable in a relation with a value that depends on the value of the independent variable

If any vertical line drawn on the graph of a relation passes through no more than one point on the graph for each value of x in the domain, then the relation is a function

A way to name a function that is defined by an equation. In function notation, the equation y=3x-8 is written as f(x) = 3x - 8

Determine Whether a Relation is a Function

A. Determine whether the relation is a function. Explain.

(3, 48), (7, 21), (5, 15), (1, 13), (2, 12)

Answer: Yes; this is a function because each x-value is paired with only one y-value.

Determine Whether a Relation is a Function

B. Determine whether the relation is a function. Explain.

Answer: No; this is not a function because 3 in the domain is paired with more than one value in the range.

A. A

B. B

C. C

D. D

A. It is a function because each x-value is paired with only one y-value.

B. It is a function because each y-value is paired with only one x-value.

C. It is not a function because an x-value is paired with more than one y-value.

D. It is not a function because a y-value is paired with more than one x-value.

A. Determine whether the relation is a function. Explain. {(1, 5), (–2, 7), (3, 8), (4, 5)}

A. A

B. B

C. C

D. D

B. Determine whether the relation is a function. Explain.

A. It is a function because each x-value is paired with only one y-value.

B. It is a function because each y-value is paired with only one x-value.

C. It is not a function because an x-value is paired with more than one y-value.

D. It is not a function because a y-value is paired with more than one x-value.

Use a Graph to Identify Functions

Determine whether the graph is a function. Explain your answer.

Answer: No; The graph is not a function because it does not pass the vertical line test. When x = 7, there are two different y-values.

A. A

B. B

C. C

D. D

Determine whether the graph is a function. Explain.

A. It is a function because each domain value is paired with only one range value.

B. It is a function because each range value is paired with only one domain value.

C. It is not a function because a domain value is paired with more than one range value.

D. It is not a function because a range value is paired with more than one domain value.

Find a Function Value

A. If f(x) = 6x + 5, what is the function value of f(5)?

f(x) = 6x + 5 Write the function.

f(5) = 6 ● 5 + 5 Replace x with 5.

f(5) = 35 Simplify.

Answer: 35

Find a Function Value

B. If f(x) = 6x + 5, what is the function value of f(–4)?

f(x) = 6x + 5 Write the function.

f(–4) = 6 ● (–4) + 5 Replace x with –4.

f(–4) = –19 Simplify.

Answer: –19

A. A

B. B

C. C

D. D

A. –5

B. –1

C. 1

D. 5

A. If f(x) = 2x – 7, what is the value of f(4)?

A. A

B. B

C. C

D. D

A. –13

B. –10

C. 10

D. 13

B. If f(x) = 2x – 7, what is the value of f(–3)?

Use Function Notation

A. GREETING CARDS Ms. Newman spent $8.82 buying cards that sold for $0.49 each. Use function notation to write an equation that gives the total cost as a function of the number of cards purchased.

Answer: t(c) = 0.49c

Use Function Notation

B. GREETING CARDS Ms. Newman spent $8.82 buying cards that sold for $0.49 each. Use the equation to determine the number of cards purchased.

t(c) = 0.49c Write the function.

8.82 = 0.49c Replace t(c) with 8.82.

18 = c Divide each side by 0.49.

Answer: So, Mrs. Newman bought 18 cards.

A. A

B. B

C. C

D. D

A. t(c) = 0.59c

B. c = 0.59 ● t(c)

C. t(c) = 0.59 + c

D. c = 0.59 + t(c)

A. CANDY BARS Erik bought candy bars that cost $0.59 cents each. Which function describes his purchase if t(c) = total cost and c = the number of candy bars?

A. A

B. B

C. C

D. D

A. 5 candy bars

B. 6 candy bars

C. 8 candy bars

D. 9 candy bars

B. CANDY BARS Erik bought candy bars that cost $0.59 cents each and spent $4.72. If t(c) = total cost and c = the number of candy bars, use the function t(c) = 0.59c to find the number of candy bars purchased.