1. Splash Screen

2. Five-Minute Check (over Chapter 7) Then/Now New Vocabulary
Example 1: Determine Whether a Relation is a Function
Example 2: Use a Graph to Identify Functions
Example 3: Find a Function Value
Example 4: Real-World Example: Use Function Notation
Lesson Menu

3. Find 24 inches to 6 feet expressed in simplest form.
A. 3 to 1
B. 12 to 1
C. 1 to 3
D. 1 to 6
5-Minute Check 1

4. Find 0.045 expressed as a percent.
B. 0.45%
C. 4.5%
D. 45%
5-Minute Check 2

5. Find 65% expressed as a fraction in simplest form.B. C. D.
5-Minute Check 3

6. 30 is 40% of what number?
A. 40
B. 50
C. 60
D. 75
5-Minute Check 4

7. A pair of sneakers that normally sells for $85 is on sale at a 20% discount. What is the sale price of the sneakers?
A. $68
B. $67
C. $66
D. $65
5-Minute Check 5

8. 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?
A. 26
B. 52
C. 78
D. 156
5-Minute Check 6

9. Determine whether a relation is a function.
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.
Then/Now

10. independent variable dependent variable vertical line test
function notation
Vocabulary

11. A. Determine whether the relation is a function. Explain.
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.
Example 1A

12. B. Determine whether the relation is a function. Explain.
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.
Example 1B

13. A. 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.
Example 1 CYP A

14. 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.
Example 1 CYP B

15. Determine whether the graph is a function. Explain your answer.
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.
Example 2

16. 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.
Example 2

17. A. If f(x) = 6x + 5, what is the function value of f(5)?
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 ● Replace x with 5.
f(5) = 35 Simplify.
Answer: 35
Example 3A

18. B. If f(x) = 6x + 5, what is the function value of f(–4)?
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
Example 3B

19. A. If f(x) = 2x – 7, what is the value of f(4)?
B. –1
C. 1
D. 5
Example 3 CYP A

20. B. If f(x) = 2x – 7, what is the value of f(–3)?
C. 10
D. 13
Example 3 CYP B

21. 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
Example 4A

22. t(c) = 0.49c Write the function. 8.82 = 0.49c Replace t(c) with 8.82.
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.
Example 4B

23. A. CANDY BARS Erik bought candy bars that cost $0. 59 cents each
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. t(c) = 0.59c
B. c = 0.59 ● t(c)
C. t(c) = c
D. c = t(c)
Example 4 CYP A

24. B. CANDY BARS Erik bought candy bars that cost $0
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.
A. 5 candy bars
B. 6 candy bars
C. 8 candy bars
D. 9 candy bars
Example 4 CYP B

25. End of the Lesson