C Challenge

35. Reasoning Can the graph of a function be a horizontal line? A vertical line? Explain.
36. To form the inverse of a relation written as a set of ordered pairs, you switch the coordinates of each ordered pair. For example, the inverse of the relation {(1, 8), (3, 5), (7, 9)} is {(8, 1), (5, 3), (9, 7)}. Give an example of a relation that is a function, but whose inverse is not a function.

Use the functions f ( x ) = 2 x bold italic f open bold italic x close equals 2 bold italic x  and g ( x ) = x 2 + 1 bold italic g open bold italic x close equals , bold italic x squared , plus 1  to find the value of each expression.

37. f ( 3 ) + g ( 4 ) f open 3 close plus g open 4 close
38. g ( 3 ) + f ( 4 ) g open 3 close plus f open 4 close
39. f ( 5 ) − 2 · g ( 1 ) f open 5 close minus 2 middle dot g open 1 close
40. f ( g ( 3 ) ) f open g open 3 close close

Standardized Test Prep

GRIDDED RESPONSE

SAT/ACT

41. What is the value of the function f(x) = 7x when x = 0.75?
42. Andrew needs x dollars for a snack. Scott needs 2 more dollars than Andrew, but Nick only needs half as many dollars as Andrew. Altogether they need $17 to pay for their snacks. How many dollars does Nick need?
43. What is the greatest number of $.43 stamps you can buy for $5?
44. What is the greatest possible width of the rectangle, to the nearest inch?

Mixed Review

See Lesson 4-5.

Write a function rule to represent each situation.

45. You baby-sit for $5 per hour and get a $7 tip. Your earnings E are a function of the number of hours h you work.
46. You buy several pairs of socks for $4.50 per pair, plus a shirt for $10. The total amount a you spend is a function of the number of pairs of socks s you buy.

    See Lesson 4-1.

47. The graph shows a family's distance from home as they drive to the mountains for a vacation.

    1. What are the variables in the graph?
    2. Copy the graph. Describe how the variables are related at various points on the graph.
    3. 
       Image Long Description

Get Ready! To prepare for Lesson 4-7, do Exercises 48–50.

See Lesson 1-2.

Evaluate each expression for x = 1, 2, 3, and 4.

48. 9 + 3 ( x − 1 ) 9 plus 3 open x minus 1 close
49. 8 + 7 ( x − 1 ) 8 plus 7 open x minus 1 close
50. 0.4 − 3 ( x − 1 ) 0.4 minus 3 open x minus 1 close

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