Page 172 - Basic College Mathematics with Early Integers

S E C T I O N 2.5 I MULTIPLYING AND DIVIDING INTEGERS 149

121. In 2005, there were 13,922 new movie titles 122. In 1987, there were only 27 California Condors in
released on DVD. In 2007, this number of releases the world.The condors in the wild were captured by
on DVD dropped to 12,050. (Source: Motion the U.S. Fish and Wildlife Service in an aggressive
Picture Association:Worldwide Market Research) move to rebuild the population by breeding them in
a. Find the change in the number of new movie captivity and releasing the chicks to the wild.
titles released on DVD from 2005 to 2007. Thanks to this effort, the condor population
increased to approximately 335 birds in 2009.
(Source: Arizona Game and Fish Department)
b. Find the average change per year in the number
of new movies released on DVD over this a. Find the change in the number of California
period. Condors from 1987 to 2009.
b. Find the average change per year in the
California Condor population of the period in
part a.

Review

Perform each indicated operation. See Section 1.9.

#
#
2
123. 90 + 12 - 5 3 124. 3 17 - 42 + 2 5 2 125. 12 , 4 - 2 + 7 126. 12 , 14 - 22 + 7

Concept Extensions

Mixed Practice (Sections 2.3, 2.4, 2.5) Perform the indicated operations.

127. -87 , 3 128. -91-102 129. -9 - 10

130. -4 + 1-32 + 21 131. -4 - 15 - 1-112 132. -16 - 1-22

Solve. For Exercises 133 and 134, see the first Concept Check in this section.

133. What is the sign of the product of seven negative 134. What is the sign of the product of ten negative
numbers? numbers?

Without actually finding the product, write the list of numbers in Exercises 135 and 136 in order from least to greatest.
For help, see a helpful hint box in this section.

12 17 12 17 50 55 15 20 23
135. 1-22 , 1-22 , 1-52 , 1-52 136. 1-12 , 1-12 , 0 , 1-72 , 1-72

137 In your own words, explain how to divide two 138. In your own words, explain how to multiply two
integers. integers.