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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

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

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

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

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

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

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

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

independent variable dependent variable vertical line test function notation Vocabulary

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

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

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

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

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

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

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 ● 5 + 5 Replace x with 5. f(5) = 35 Simplify. Answer: 35 Example 3A

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

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

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

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

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

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) = 0.59 + c D. c = 0.59 + t(c) Example 4 CYP A

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

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