©Apply
7z2 + 23z + 6
z 2 + 2 z — 3
3z2 + 12z
Simplify e a ch expression. State an y ex clu d ed values.
31.r 2 + 1 0 r + 2 5^2 r 9r — 5 32. 33.
5t2 + 6 t~ 8
3t2 + 5 t - 2
34.
37.
32a
16a2 - 8a
4a2 - 8a - 5
15 - a - 2 a 2
35.
- 16 + 16m + 3mm 2 _3m — 28
36.
39.
2s2 + s
10c + c2 - 3c3
5c2 - 6c - 8
- Think About a Plan In th e figure at th e right, w h at is the
ratio of the area of th e sh ad e d triangle to th e area of the
rectangle? Write your answ er in sim plified form.- W hat is an expression for th e length of th e rectangle?
- How do you find th e area of a triangle?
- Writing Is ^ T T t^ie sam e as x - 3? Explain.
^2 5 1 42. a. Construction To keep h eating costs dow n for a building, architects w an t th e
ratio of surface area to volum e to be as sm all as possible. W hat is an expression
for the ratio of surface area to volum e for each figure?
i. square prism ^7 ii. cylinder
j—
b. For each figure, w h at is th e ratio of surface area to volum e w h en
b = 12 ft, h = 18 ft, an d r = 6 ft?
- Error Analysis A stu d en t sim plified a rational expression as
show n at th e right. D escribe an d correct th e error. - Banking A b an k account w ith principal P earns interest at rate
r (expressed as a decim al), co m p o u n d ed annually. W hat is the
ratio of th e balance after 3 yr to th e balance after 1 yr? Write r
as a decim al. - Open-Ended W rite a rational expression th a t has 4 a n d —3 as excluded values.
Write a ratio in simplified form of the area of the shaded figure to the area of the
figure that encloses it.
3x
Challenge Simplify each expression. State any excluded values.
- nr
m2 + lim n + 10 n2 49.
q2 — 5 ab + 6 b2
a2 + 2 ab — 8 b2 50.
36v2 - 49 w2
18v2 + 9vw - 14 w2
6 6 8 C h a p t e r 11 Rat io nal Expressions and Funct ions