1. EXAMPLE 7 Solve a multi-step problem Printing Costs You are creating brochures that promote your school’s sports events. You pay $20 for computer time. The cost of printing a brochure is $.60. Write and graph an equation that gives the average cost C (in dollars per brochure) as a function of the number b of brochures printed.

2. EXAMPLE 7 Solve a multi-step problem STEP 1 Write a verbal model. Then write an equation. C 20 + 0.6 b b SOLUTION =

3. EXAMPLE 7 Solve a multi-step problem 20 + 0.6 b b C = = + 20 b 0.6b b 20 b = + 0.6 Rewrite the rational function. STEP 2

4. EXAMPLE 7 Solve a multi-step problem STEP 3 Graph the function.

5. GUIDED PRACTICE for Example 7 8. WHAT IF? In Example 7, suppose the cost of printing a brochure is $. 80. Write and graph an equation that gives the average cost C (in dollars per brochure) as a function of the number b of brochures printed. 20 b C = + 0.8 ANSWER

6. GUIDED PRACTICE for Example 7 9. INTERNET COSTS A cable Internet service provider charges an installation fee of $100 and a monthly service charge of $45. Write and graph an equation that gives the average cost C (in dollars per month) as a function of the number m of months of Internet service. = + 45 100 m ANSWER