Answers and Explanations 159
Answers
1–100
As x approaches ∞, you have
lim
lim x
x
x
x
x
x
x
→∞
→∞
−
+
−
+
− )
(
=
−
( )
= −∞
7
33
51
19
1
7
9
8
7
4
9
Likewise, the limit here is negative because a positive number raised to an odd power
(or any power for that matter!) is positive, but after multiplying by –7, the answer
becomes negative.
83.
3x + 12
Remove the parentheses and combine like terms:
(
) (
)
5
6
2
6
5
6 2
6
3
12
x
x
x
x
x
+ + − +
=
+ −
+
=
+
84.
3x – 2
Remove the parentheses and combine like terms:
2
7
2
4
9
2
7 2
4
9
3
2
2
2
2
2
x
x
x
x
x
x
x
x
x
− +
(
) + − + −
(
)
=
− + −
+
−
=
−
85.
x
3
– x
2
+ 2x + 14
Remove the parentheses and combine like terms:
x
x
x
x
x
x
x
x
x
x
x
3
2
2
3
2
2
3
2
5
6
4
2
8
5
6 4
2
8
2
14
−
+
(
) +
+
+
(
)
=
−
+ +
+
+
=
−
+
+
86.
–2x
4
+ 3x + 8
Remove the parentheses and combine like terms:
3
2
3
6
3
2 3
6
2
3
8
4
4
4
4
4
x x
x
x x
x
x
x
+
+
(
) + − +
(
)
=
+
+ −
+
= −
+
+
87.
x
4
+ 5x
3
– 3x
2
Remove the parentheses and combine like terms:
x
x
x
x
x
x
x
x
x
x
x
4
2
3
2
4
2
3
2
4
3
2
6
3
5
3
3
6
3 5
3
3
5
3
−
+
(
) +
+
−
(
)
=
−
+ +
+
−
=
+
−