1. Main Idea/Vocabulary linear function Represent linear functions using function tables and graphs.

2. Example 1 MUSIC During a clearance sale, a music store is selling CDs for $3 and tapes for $1. Graph the function 3x + y = 6 to find how many CDs and tapes Bill can buy with $6. Graph a Function First, rewrite the equation by solving for y. 3x + y=6Write the equation. 3x – 3x + y=6 – 3xSubtract 3x from each side. y=6 – 3xSimplify.

3. Example 1 Choose values for x and substitute them to find y. Then graph the ordered pairs. Answer: The solutions are 0 CDs and 6 tapes, 1 CD and 3 tapes, or 2 CDs and 0 tapes. Graph a Function

4. 1.A 2.B 3.C 4.D Example 1 BAKE SALE During a bake sale, a plate of brownies is sold for $2 and a plate of cookies is sold for $1. Graph the function 2x + y = 4. Which is not a combination of plates of brownies and cookies Craig can buy with $4? A.2 plates of brownies, 0 plates of cookies B.1 plate of brownies, 2 plates of cookies C.1 plate of brownies, 3 plates of cookies D.0 plate of brownies, 4 plates of cookies

5. CS

6. Example 2 Graph a Function Graph y = x – 3. Step 1Choose some values for x. Make a function table. Include a column of ordered pairs of the form (x, y).

7. Example 2 Graph a Function Step 2Graph each ordered pair. Draw a line that passes through each point. Answer: Note that the ordered pair for any point on this line is a solution of y = x – 3. The line is the complete graph of the function.

8. Example 2 Graph a Function CheckIt appears from the graph that (–1, –4) is also a solution. Check this by substitution. y= x – 3Write the function. ? –4= –1 – 3Replace x with –1 and y with –4. –4= –4Simplify.

9. 1.A 2.B 3.C 4.D Example 2 Graph y = x –2. A.B. C.D.

10. Example 3 Which line graphed below best represents the table of values for the ordered pairs (x, y)? A.B. C.D.

11. Example 3 Solve the Item The values in the table represent the ordered pairs (0, 1), (1, 3), (2, 5), and (3, 7). Answer: D Read the Item You need to decide which of the four graphs represents the data in the table. Test the ordered pairs with each graph. Graph D is the only graph which contains all these ordered pairs. The answer is D.

12. 1.A 2.B 3.C 4.D Example 3 Which line graphed below best represents the table of values for the ordered pairs (x, y)? A.B. C.D.

13. 1.A 2.B 3.C 4.D Five Minute Check 1 (over Lesson 9-2) A.4 B.9 C.15 D.36 Find f(3) if f(x) = x + 12.

14. 1.A 2.B 3.C 4.D Five Minute Check 2 (over Lesson 9-2) Find f(5) if f(x) = 4x. A.AnsA B.AnsB C.AnsC D.AnsD

15. 1.A 2.B 3.C 4.D Five Minute Check 3 (over Lesson 9-2) A.2 B.11 C.12 D.13 Find f(6) if f(x) = 2x – 1.

16. 1.A 2.B 3.C 4.D Five Minute Check 4 (over Lesson 9-2) A.–23 B.–21 C.21 D.23 Find f(–7) if f(x) = –3x + 2.

17. 1.A 2.B 3.C 4.D Five Minute Check 5 Elizabeth is buying candles. They are $5.43 each. She is not sure how many she wants to buy. Write a function to calculate the total cost for any given number of candles. (over Lesson 9-2) A.f(x) = 5.43x B. C.f(x) = 5.43 + x D.f(x) = 5.43 – x

18. 1.A 2.B 3.C 4.D Five Minute Check 6 (over Lesson 9-2) A.y = x + 45 B.y = 3x C.y = 3x + 4 D.y = 2x + 3 Which function matches the function table?

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