题目内容
已知x=
-
,y=
,求(
+
)÷
的值.
| 3 |
| 2 |
| 2 |
| 1 |
| x-y |
| 1 |
| x+y |
| xy |
| x2-y2 |
原式=
×
=
,
当y=
时,
=
=
.
| 2x |
| (x+y)(x-y) |
| (x+y)(x-y) |
| xy |
| 2 |
| y |
当y=
| 2 |
| 2 |
| y |
| 2 | ||
|
| 2 |
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题目内容
| 3 |
| 2 |
| 2 |
| 1 |
| x-y |
| 1 |
| x+y |
| xy |
| x2-y2 |
| 2x |
| (x+y)(x-y) |
| (x+y)(x-y) |
| xy |
| 2 |
| y |
| 2 |
| 2 |
| y |
| 2 | ||
|
| 2 |