题目内容
计算:
(1)4a2b÷(-
)2•(-
);
(2)
÷
•
.
(1)4a2b÷(-
| a |
| 2b |
| b |
| 8a |
(2)
| 2x-6 |
| x2-4x+4 |
| 3-x |
| x2+6x+9 |
| 2-x |
| x+3 |
分析:根据分式除法运算,除以一个分式,等于乘以这个分式的倒数,再根据分式乘法运算,约去公因式,可的计算结果;
解答:解:(1)4a2b÷(-
)2•(-
)
=4a2b÷(
)•(-
)
=4a2b•
•(-
)
=
;
(2)
÷
•
=
•
•
=
.
| a |
| 2b |
| b |
| 8a |
=4a2b÷(
| a2 |
| 4b2 |
| b |
| 8a |
=4a2b•
| 4b2 |
| a2 |
| b |
| 8a |
=
| -2b4 |
| a |
(2)
| 2x-6 |
| x2-4x+4 |
| 3-x |
| x2+6x+9 |
| 2-x |
| x+3 |
=
| 2x-6 |
| (x-2)2 |
| (x-3)2 |
| 3-x |
| 2-x |
| x+3 |
=
| 2x2-12x+18 |
| x2-x-6 |
点评:本题考查了分式的乘除法,先算乘方,再算乘除,把除变成乘,约去公因式,的最简分式.
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