CHAPTERS 1–7 Cumulative Review Exercises 491Rewrite each rational expression with the given denominator.Add or subtract. Write each answer in lowest terms.Simplify each complex fraction.Solve.
- for D
Solve each problem.
23.A boat goes 7 mph in still water. It takes as long to go 20 mi upstream as 50 mi down-
stream. Find the rate of the current.
24.Sanford Geraci can paint a room in his house, working alone, in 5 hr. His neighbor can do
the job in 4 hr. How long will it take them to paint the room if they work together?
25.If xvaries directly as y, and when , find xwhen.
26.Under certain conditions, the length of time that it takes for fruit to ripen during the grow-
ing season varies inversely as the average maximum temperature during the season. If it
takes 25 days for fruit to ripen with an average maximum temperature of , find the
number of days it would take at 75°. Round your answer to the nearest whole number.80°x= 12 y= 4 y= 9F=
k
d-D2 x
x- 3+
1
x+ 3=- 6
x^2 - 9
3 x
x+ 1=
3
2 x1
x+ 3- 1
1 +
1
x+ 32 p
k^2
3 p^2
k^33
2 m^2 - 9 m- 5- m+ 1
2 m^2 - m- 1
x+ 1
3 - x+
x^2
x- 3- 4
y+ 2
+6
5 y+ 104 x+ 2
x+ 5+- 2 x+ 8
x+ 5
3
6 m- 12=
?
42 m- 8415
4 p=
?
64 p^3CUMULATIVE REVIEW EXERCISES
CHAPTERS 1–7
1.Use the order of operations to evaluate.Solve.
- for b
6.Consider the graph of.
(a)What is the x-intercept? (b)What is the y-intercept?Sketch each graph.Solve each system.y=- 3 x+ 2 y=-x^2 + 14 x+ 3 y=- 125 y... 6 y+ 82 +m
2 - m
=3
4a=1
2312 y- 52 = 2 + 5 y bh3 + (^4) A^12 -^34 B
9.
5 x+ 2 y= 1
4 x- y=- 7 10.
10 x+ 4 y= 12
5 x+ 2 y= 7