33. Forestry A forester plants a tree and measures its circumference yearly over the next four years. The table shows the forester's measurements.

    Tree Growth

    Time (yr)	1	2	3	4
    Circumference (in.)	2	4	6	8

    1. Show that the data are linear, and write an equation that models the data.
    2. Predict the circumference of the tree after 10 yr.
    3. The circumference of the tree after 10 yr was actually 43 in. After four more years, the circumference was 49 in. Based on this new information, does the relationship between time and circumference continue to be linear? Explain.

Standardized Test Prep

SAT/ACT

34. A company's revenue has been increasing by $20,000 each year. In 2011, the revenue was $730,000. Which is an equation that gives the company's revenue y (in thousands of dollars) x years after 2000?

    1. y − 730 = 20 ( x − 11 ) y minus 730 equals 20 open x minus 11 close
    2. x − 11 = 20 ( y − 730 ) x minus 11 equals 20 open y minus 730 close
    3. y = 20 x + 730 y equals 20 x plus 730
    4. x = 20 y + 11 x equals 20 y plus 11

35. Which equation is equivalent to y + 12 = − 3 ( x − 2 ) ? y plus 12 equals negative 3 open x minus 2 close question mark

    6. y = − 15 ( x − 2 ) y equals negative 15 open x minus 2 close
    7. y = − 3 x − 14 y equals negative 3 x minus 14
    8. y = − 3 x − 6 y equals negative 3 x minus 6
    9. y = 9 x + 6 y equals 9 x plus 6

36. Which number is NOT a solution of 6 ≥ | x − 2 | ? 6 greater than or equal to vertical line x minus 2 vertical line question mark

    1. − 3 negative 3
    2. 0
    3. 8
    4. 10

Short Response

37. The table shows the number of text messages sent from a cellular phone and the monthly cost of the phone plan.

    Phone Plan Cost

    Text Messages Sent	20	50	80
    Monthly Cost ($)	41.99	44.99	47.99

    1. Graph the data.
    2. What is an equation that represents the relationship between the number of messages sent n and the monthly cost c?

Mixed Review

See Lesson 5-3.

Find the slope and y -intercept of the graph of each equation.

38. y = x + 4 y equals x plus 4
39. y = 6 x y equals 6 x
40. y = − x − 13 y equals negative x minus 13

Get Ready! To prepare for Lesson 5-5, do Exercises 41–43.

See Lesson 2-5.

Solve each equation for y.

41. 7 x y = z 7 x y equals z
42. a y − 3 = 7 b eh y minus 3 equals 7 b
43. 6 ( x − y ) = c 6 open x minus y close equals c

Table of Contents