题目内容
化简(x-2-y-2)÷(x-1+y-1)的结果是( )
A.
| B.
| C.
| D.
|
原式=(
-
)÷(
+
)
=
÷
=
•
=
,
故选:B.
| 1 |
| x2 |
| 1 |
| y2 |
| 1 |
| x |
| 1 |
| y |
=
| y2-x2 |
| x2y2 |
| y+x |
| xy |
=
| (y+x)(y-x) |
| (xy)2 |
| xy |
| y+x |
=
| y-x |
| xy |
故选:B.
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