Section 2.2 Linear Equations and Applications

Problems are from pages 71 to 76

Page 72, problem 16

Solve S = 2prh + 2pr2 for h
• Move the term containing h to the left side and the S to the right side
• -2prh = 2pr2 - S
• Divide by -2pr to get h = [-S + 2pr2]/-2pr
• Final answer is h = [S - 2pr2]/2pr

Page 74, problem 36

Basic mixture is 35% acid. Total mixture is 40 liters. How much of the mixture is water?
• Is 35% is Acid 65% must be Water. Total must be 100%
• 0.65 = Water/40
• Water = 40 x 0.65 = 26 liters of water

Page75, problem 40

Loan called for 36 monthly payments. Total finance charge was \$600. He paid off loan 12 payments early.
• f = 600, k = 12 and n = 36
• u = 600 * [12*(12+1)]/[36*(36+1)]
• u = \$70.27 unearned interest

Page 76, problem 46

In 1982 how many of a group of 110,000 viewers watched independent stations?
• Total = 110,00 and the percent watching independent stations was 21%
• 0.21 = Viewers/Total = Viewers/110,000
• Viewers = 0.21 * 110,000 = 23,100 viewers watched independent stations