题目内容
先化简,再求值(
-a+1)÷
,其a=
+2.
3 |
a+1 |
a2-4a+4 |
a+1 |
2 |
原式=
÷
,
=
•
,
=-
,
当a=
+2时,原式=-
=-
=-1-2
.
3-(a+1)(a-1) |
a+1 |
(a-2)2 |
a+1 |
=
-(a+2)(a-2) |
a+1 |
a+1 |
(a-2)2 |
=-
a+2 |
a-2 |
当a=
2 |
a+2 |
a-2 |
| ||
|
2 |
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