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