Beginning Algebra, 11th Edition

Determine the solution set of each quadratic equation by observing the corresponding

screens. Then use the method of your choice to verify your answers by solving the

quadratic equation.

21.

22. 2 x^2 - x- 3 = 0

x^2 - x- 6 = 0

586 CHAPTER 9 Quadratic Equations

10

–10

–10 10

10

–10

–10 10

2.1

• 4.1


• 4.7 4.7

2.1

• 4.1


• 4.7 4.7

Find the domain and range of each function graphed in the indicated exercise.

23.Exercise 13 24.Exercise 14 25.Exercise 15

26.Exercise 16 27.Exercise 17 28.Exercise 18

Given ,find each of the following.

Solve each problem.

33.Find two numbers whose sum is 80 and whose product is a maximum. (Hint:Let x

represent one of the numbers. Then represents the other. A quadratic function rep-

resents their product.)

34.Find two numbers whose sum is 300 and whose product is a maximum.

35.The U.S. Naval Research Laboratory designed a giant radio telescope that had a diameter

of 300 ft and a maximum depth of 44 ft. The graph depicts a cross section of that tele-

scope. Find the equation of this parabola. (Source:Mar, J., and H. Liebowitz, Structure

Technology for Large Radio and Radar Telescope Systems,The MIT Press.)

80 - x

ƒ 102 ƒ 112 ƒ 1 - 22 ƒ 1 - 12

ƒ 1 x 2 = 2 x^2 - 5 x+ 3

(–150, 44) (150, 44)

x

y

50

–150–100 –50 050100 150

36.Suppose the telescope in Exercise 35had a diameter of 400 ft and a maximum depth of

50 ft. Find the equation of this parabola.

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