题目内容
先化简(
-
)÷
,再从-1、0、1三个数中,选择一个你认为合适的数作为x的值代入求值.
| x |
| x-1 |
| 1 |
| x+1 |
| 1 |
| x2-1 |
原式=
-
,
=
,
=
,
∴(
-
)÷
=
•
=x2+1.
取x=0代入上式得,
=02+1
=1.
| x(x+1) |
| (x-1)(x+1) |
| x-1 |
| (x-1)(x+1) |
=
| x2+x-x+1 |
| (x-1)(x+1) |
=
| x2+1 |
| x2-1 |
∴(
| x |
| x-1 |
| 1 |
| x+1 |
| 1 |
| x2-1 |
| x2+1 |
| x2-1 |
| x2-1 |
| 1 |
取x=0代入上式得,
=02+1
=1.
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