85. 86.
87. 88.
89. 90.
91. 92.
Brain Busters Multiply or divide as indicated.93.94.
95.
96.
Add or subtract as indicated. See Section 1.2.99. 100.-
2
3
+a-4
7
b-1
8
4
7
+
1
3
-
1
2
9
10
- a-
1
3
- b
3
4
+
1
12
PREVIEW EXERCISES
a2 x^3 + 3 x^2 - 2 x
3 x- 15,
2 x^3 - x^2
x^2 - 3 x- 10b#
5 x^2 - 10 x
3 x^2 + 12 x+ 12a6 k^2 - 13 k- 5
k^2 + 7 k,
2 k- 5
k^3 + 6 k^2 - 7 kb#
k^2 - 5 k+ 6
3 k^2 - 8 k- 316 c^2 + 24 cd+ 9 d^2
16 c^2 - 16 cd+ 3 d^2,
16 c^2 - 9 d^2
16 c^2 - 24 cd+ 9 d^23 k^2 + 17 kp+ 10 p^2
6 k^2 + 13 kp- 5 p^2,
6 k^2 +kp- 2 p^2
6 k^2 - 5 kp+p^28 a^2 - 6 a- 9
6 a^2 - 5 a- 6,
4 a^2 + 11 a+ 6
9 a^2 + 12 a+ 46 x^2 + 5 x- 6
12 x^2 - 11 x+ 2,
4 x^2 - 12 x+ 9
8 x^2 - 14 x+ 3p^3 - 27 q^3
p^2 +pq- 12 q^2#p
(^2) - 2 pq- 24 q 2
p^2 - 5 pq- 6 q^2
a 3 - 8 b^3
a^2 - ab- 6 b^2
#a
(^2) +ab- 12 b 2
a^2 + 2 ab- 8 b^2
64 x 3 + 1
4 x^2 - 100
#^4 x+^20
64 x^2 - 16 x+ 4
8 x^3 - 27
2 x^2 - 18
#^2 x+^6
8 x^2 + 12 x+ 18
x 3 +y^3
2 x+ 2 y
,
x 2 - y^2
2 x- 2 ya 3 - b^3
a^2 - b^2,
2 a- 2 b
2 a+ 2 b8.4 Adding and Subtracting Radical Expressions
OBJECTIVES
Adding and Subtracting Rational Expressions
7.2
1 Add and subtract
rational expressions
with the same
denominator.
2 Find a least
common
denominator.
3 Add and subtract
rational expressions
with different
denominators.
OBJECTIVE 1 Add and subtract rational expressions with the same
denominator. We do this as we would with rational numbers.
Adding or Subtracting Rational Expressions
Step 1 If the denominators are the same,add or subtract the numerators.
Place the result over the common denominator.
If the denominators are different,first find the least common de-
nominator. Write all rational expressions with this least common
denominator, and then add or subtract the numerators. Place the
result over the common denominator.
Step 2 Simplify.Write all answers in lowest terms.