PreAlgebra_Chapter_8_Lesson_1_Functions.pdf

Transcript

1. Over Chapter 7 Find 4 feet to 6 feet expressed in simplest form. Find 0.045 expressed as a percent. Find 65% expressed as a fraction in simplest form. 30 is 40% of what number? A pair of sneakers that normally sells for $85 is on sale at a 20% discount. What is the sale price of the sneakers?
2. Over Chapter 7 2. 4.5% 1. 1 to 3 3. 4. 75 5. $68
3. Over Chapter 7 • Find the procedures in your notes (should be in the front). • Review and think of two that you would like to improve.
4. Objectives 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
5. • Determine whether a relation is a function. (10 lines) • Write a function using function notation.
6. • vertical line test • function notation
7. 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.
8. 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.
9. 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)}
10. 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.
11. 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.
12. 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.
13. 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) = 30 + 5 Simplify. f(5) = 35 Simplify. Answer: 35
14. 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) = –24 + 5 Simplify. f(–4) = –19 Simplify. Answer: –19
15. A. –5 B. –1 C. 1 D. 5 A. If f(x) = 2x – 7, what is the value of f(4)?
16. A. –13 B. –10 C. 10 D. 13 B. If f(x) = 2x – 7, what is the value of f(–3)?
17. Use Function Notation A. GREETING CARDS Ms. Newman spent some money 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
18. 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.
19. 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?
20. 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.
21. • Turn and talk – How do you test a function to see if it really is a faction (2 ways)?
22. • 401 1-9
23. • Homework: 402 10-30 Even