题目内容
化简:
(1)
+
-
;
(2)(1+
)÷
.
(1)
| x+2y |
| y-x |
| y |
| x-y |
| 2x |
| y-x |
(2)(1+
| 1 |
| x |
| x2-1 |
| x |
分析:(1)把第二箱的分母变成y-x,再计算即可;
(2)先算括号里的,再算括号外的即可.
(2)先算括号里的,再算括号外的即可.
解答:解:(1)原式=
-
-
=
=
=1;
(2)原式=
×
=
.
| x+2y |
| y-x |
| y |
| y-x |
| 2x |
| y-x |
| x+2y-y-2x |
| y-x |
| -x+y |
| y-x |
(2)原式=
| x+1 |
| x |
| x |
| (x+1)(x-1) |
| 1 |
| x-1 |
点评:本题考查了分式的混合运算,解题的关键是注意分子、分母的因式分解.
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