Page 735 - Basic College Mathematics with Early Integers

A PPEND I X B .1 I ADDING AND SUBTRACTING POLYNOMIALS 711

An object is dropped from the deck of the Royal Gorge Bridge, which stretches across Royal Gorge at a height of
1053 feet above the Arkansas River.The height of the object above the river after t seconds is given by the polynomial
1053 - 16t 2

Use this polynomial for Exercises 55 and 56. (Source: Royal Gorge Bridge Co.)

55. How far above the river is an object that has been 56. How far above the river is an object that has been
falling for 3 seconds? falling for 8 seconds?

Concept Extensions

Find the perimeter of each figure.

57. 58. (x 6)
2
(5x 10) (2x 1) inches meters
inches (x 1)
meters
(x 11) inches (3x 10)
meters
2
(5x 2x)
meters

Given the lengths in the figure below, we find the unknown length by subtracting. Use the information to find the
unknown lengths in Exercises 59 and 60.

8 units

3 units ?
(8 3) units
59. 60. (x 7x 6) units
2
(7x 10) units
2
(x 2) ?
units units
?
units
(3x 5)
units

Fill in the blanks.

2
2
2
61. 13x + x - 2 + 1 x - 6x + 22 = 5x + 14x - 4

2
2
2
62. 1 y + 4y - 32 + 18y - y + 2 = 9y + 2y + 7
2
4
63. Find the value of 7a - 6a + 2a - 1 when a = 1.2.

3
2
64. Find the value of 3b + 4b - 100 when b =-2.5.

65. For Exercises 55 and 56, the polynomial 1053 - 16t 2 was used to give the height of an object above the river
after t seconds. Find the height when t = 8 seconds and t = 9 seconds. Explain what happened and why.