题目内容
先化简下面的代数式,再求值:
-
,其中x=
| x2+3 |
| x2-1 |
| x-1 |
| x+1 |
| 3 |
原式=
-
=
=
=
,
当x=
时,
原式=
=
+1.
| x2+3 |
| (x+1)(x-1) |
| x-1 |
| x+1 |
=
| x2+3-x2+2x-1 |
| (x+1)(x-1) |
=
| 2(x+1) |
| (x+1)(x-1) |
=
| 2 |
| x-1 |
当x=
| 3 |
原式=
| 2 | ||
|
=
| 3 |
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