13.Concept Check When a formula is solved for a particular variable, several different
equivalent forms may be possible. If we solve for h, one possible correct answer is
Which one of the following is notequivalent to this?
A. B. C. D.
14.Concept Check The answer to Exercise 11is given as Which one of
the following is notequivalent to this?
A. B. C. D.
Solve each equation for y. See Example 4.
Solve each problem.See Example 5.
- 5 x+ 3 y= 12 6 x- 5 y= 7 8 x- 3 y= 4
4 x+ 9 y= 11 7 x+ 8 y= 11 - 3 x+ 2 y= 5
C=
5
9
C= F- 32
5 F- 160
9
C=
5 F
9
-
160
9
C=
5
9
F-
160
9
C=^59 1 F- 322.
1
2 a
b
h=
a
1
2 b
h= 2 aa h=
1
b
h= 2 a b
a
b
b
h=
2 a
b
.
a=^12 bh
SECTION 2.2 Formulas and Percent 63
- (area of a trapezoid)
(a)for h (b) for B
B
b
h
a=
1
2
h 1 b+B 2 10. for h
(surface area of a right circular cylinder)
S= 2 prh+ 2 pr^2
h
r
- for C
(Celsius to Fahrenheit)
- for F
(Fahrenheit to Celsius)
C=
5
9
F= 1 F- 322
9
5
C+ 32
21.Ryan Newman won the Daytona 500 (mile)
race with a rate of 152.672 mph in 2008.
Find his time to the nearest thousandth.
(Source:www.daytona500.com)
22.In 2007, rain shortened the Indianapolis
500 race to 415 mi. It was won by Dario
Franchitti, who averaged 151.774 mph.
What was his time to the nearest thou-
sandth? (Source:www.indy500.com)
23.Nora Demosthenes traveled from Kansas City to Louisville, a distance of 520 mi, in 10 hr.
Find her rate in miles per hour.
24.The distance from Melbourne to London is 10,500 mi. If a jet averages 500 mph between
the two cities, what is its travel time in hours?
25.As of 2009, the highest temperature ever recorded in Tennessee was 45°C. Find the corre-
sponding Fahrenheit temperature. (Source:National Climatic Data Center.)