Intermediate Algebra (11th edition)

CHAPTER 9 Review Exercises 565

9.5–9.6 Identify the vertex of each parabola.

39. 40.

41. 42.

Graph each parabola. Give the vertex, axis, domain, and range.

Solve each problem.

47.Total consumer spending on computers, peripherals, and
software in the United States for selected years is given in the
table. Let represent 1985, represent 1990, and
so on.
(a)Use the data for 1985, 1995, and 2005 in the quadratic
form to write a system of three
equations.
(b)Solve the system from part (a) to get a quadratic function ƒ
that models the data.
(c)Use the model found in part (b) to approximate
consumer spending for computers, peripherals, and
software games in 2006 to the nearest tenth. How does
your answer compare to the actual data from the table?

48.The height (in feet) of a projectile tseconds after being fired from Earth into the air is
given by

Find the number of seconds required for the projectile to reach maximum height. What is

the maximum height?

49.Find the length and width of a rectangle having a perimeter of 200 m if the area is to be a
maximum. What is the maximum area?

9.7 Solve each inequality, and graph the solution set.

50. 51.

52. 53.

54. 55.

3 t+ 4

t- 2

... 1

6

2 z- 1

62

1 x+ 221 x- 321 x+ 52 ... 0 14 x+ 322 ...- 4

1 x- 4212 x+ 3270 x^2 +x... 12

ƒ 1 t 2 =- 16 t^2 + 160 t.

ax^2 +bx+c=y

x= 0 x= 5

x=-

1

2

x= 21 y+ 322 - 4 y^2 + 6 y- 14

y= 21 x- 222 - 3 ƒ 1 x 2 =- 2 x^2 + 8 x- 5

x= 1 y- 322 - 4 y=- 3 x^2 + 4 x- 2

ƒ 1 x 2 =- 1 x- 122 ƒ 1 x 2 = 1 x- 322 + 7

Spending

(billions of

Year dollars)

1985 2.9

1990 8.9

1995 24.3

2000 43.8

2004 51.6

2005 56.5

2006 61.4

CONSUMER SPENDING ON

COMPUTERS, PERIPHERALS,

AND SOFTWARE

Source:Bureau of Economic

Analysis.

MIXED REVIEW EXERCISES

Solve.

56. for R *57. 58.

59.S= for d 60. 18 x- 722 Ú- 1 61. 2 x- 2 x= 6

Id^2

k

V=r^2 +R^2 h 3 t^2 - 6 t=- 4 13 x+ 1122 = 7

*This exercise requires knowledge of complex numbers.
(continued)