题目内容
若a+3b=0,则(1-
)÷
=______.
| b |
| a+2b |
| a2+2ab+b2 |
| a2-4b2 |
∵a+3b=0,
∴a=-3b.
∴原式=
÷
=
×
=
=
=
.
∴a=-3b.
∴原式=
| a+b |
| a+2b |
| (a+b)2 |
| (a-2b)(a+2b) |
=
| a+b |
| a+2b |
| (a-2b)(a+2b) |
| (a+b)2 |
=
| a-2b |
| a+b |
=
| -3b-2b |
| -3b+b |
=
| 5 |
| 2 |
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