Page 592 - Basic College Mathematics with Early Integers

S E C T I O N 8.1 I VARIABLE EXPRESSIONS 569

Review the commutative, associative, and distributive properties.Then identify which property allows us to write the
equivalent expression on the right side of the equal sign.

109. 612x - 32 + 5 = 12x - 18 + 5 110. 9 + 7x + 1-22 = 7x + 9 + 1-22

111. -7 + 14 + y2 = 1-7 + 42 + y 112. 1x + y2 + 11 = 11 + 1x + y2

113. If x is a whole number, which expression is the 114. If x is a whole number, which expression is the
1 1
largest: 2x,5x, or x? Explain your answer. smallest: 2x,5x, or x? Explain your answer.
3 3

Find the area of each figure.
115. (2x 1) miles 116. 12 kilometers

(3x 5)
kilometers Rectangle
7 miles Rectangle (2x 3) miles
Rectangle
Rectangle 3 miles (5x 1)
kilometers

4 kilometers

To appraise the value of a large tree in landscaping, the trunk area is used.The trunk area A is calculated with the
2
formula A = 0.7854d , where d is the diameter of the tree.
117. Tane Mahuta is the name of New Zealand’s largest 118. Lost Monarch, which was discovered only in 1998, is
known living Kauri tree. Its trunk has a diameter of a coast redwood tree in Northern California. It is
173 inches. Use the formula to find the trunk area of located among other giant redwoods in “The Grove
this tree. Round your result to the nearest tenth. of Titans,” in Jedediah Smith Redwoods State Park.
(Source: New Zealand Parks) This mammoth tree has confirmed diameter of
312 inches. Use the formula to find the trunk area of
this tree. Round your result to the nearest tenth.
(Source: Sierra Club)

Simplify.

119. 9684q - 686 - 4860q + 12,960 120. 761268x + 5922 - 2960