Page 606 - Basic College Mathematics with Early Integers

S E C T I O N 8.3 I SOLVING EQUATIONS: THE MULTIPLICATION PROPERTY 583

Concept Extensions

What operation is appropriate for solving each equation: addition or division? See the Concept Check in this section.

61. 12 = x - 5 62. 12 =-5x 63. -7x = 21 64. -7 + x = 21

65. Why does the multiplication property of equality not 66. Is the equation -x = 6 solved for the variable?
allow us to divide both sides of an equation by zero? Explain why or why not.

#
The equation d = r t describes the relationship between distance d in miles, rate r in miles per hour, and time t in hours.
If necessary, round answers to the nearest tenth.

67. The distance between New Orleans, Louisiana, and 68. The distance between Boston, Massachusetts, and
Memphis,Tennessee, by road is 390 miles. How long Milwaukee,Wisconsin, by road is 1050 miles. How
will it take to drive from New Orleans to Memphis if long will it take to drive from Boston to Milwaukee if
the driver maintains a speed of 60 miles per hour? the driver maintains a speed of 55 miles per hour?
(Source:World Almanac) (Source:World Almanac)

69. The distance between Cleveland, Ohio, and 70. The distance between St. Louis, Missouri, and
Indianapolis, Indiana, by road is 294 miles.At what Minneapolis, Minnesota, by road is 552 miles. If it
speed should a driver drive if he or she would like to took 9 hours to drive from St. Louis to Minneapolis,
make the trip in 5 hours? (Source:World Almanac) what was the driver’s average speed? (Source:World
Almanac)

Solve.

71. -0.025x = 91.2 72. 3.6y =-1.259 - 3.277

Solve.
y x
6
73. =-86 - (-1029) 74. = 4 - 5 7
72 -13

x y
2
75. = 5 - ƒ -10 ƒ - (-9) 76. = (-8) - ƒ 20 ƒ + (-2) 2
2
-2 10