题目内容
先化简,再求值:| x2-1 |
| x2-2x+1 |
| x2-5x |
| x-5 |
分析:首先对每个分式化简,然后相加,最后代入数值计算即可.
解答:解:原式=
+
•
=
+1
=
当x=-2时,原式=
=
.
| (x+1)(x-1) |
| (x-1)2 |
| x(x-5) |
| x-5 |
| 1 |
| x |
=
| x+1 |
| x-1 |
=
| 2x |
| x-1 |
当x=-2时,原式=
| -4 |
| -2-1 |
| 4 |
| 3 |
点评:本题主要考查了分式化的化简求值,注意先化简,然后代值计算.
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