题目内容
先化简,再求值:
-
÷
,其中x=2.
| 1 |
| x+2 |
| x2+2x+1 |
| x+2 |
| x2-1 |
| x-1 |
原式=
-
•
=
-
=-
;
当x=2时,原式=-
.
| 1 |
| x+2 |
| (x+1)2 |
| x+2 |
| x-1 |
| (x+1)(x-1) |
=
| 1 |
| x+2 |
| x+1 |
| x+2 |
=-
| x |
| x+2 |
当x=2时,原式=-
| 1 |
| 2 |
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