题目内容
通分
(1)
与
;
(2)
与
.
(1)
| 3c |
| 2bd |
| 2ac |
| 5b2 |
(2)
| 2mn |
| 4m2-9 |
| 3m |
| 4m2-6m+9 |
分析:(1)先找出最简公分母为10b2d,再进行通分即可;
(2)先找出最简公分母为(2m+3)(2m-3)2,再进行通分即可得出答案.
(2)先找出最简公分母为(2m+3)(2m-3)2,再进行通分即可得出答案.
解答:解:(1)
=
=
;
=
=
.
(2)
=
=
=
;
=
=
=
.
| 3c |
| 2bd |
| 3c•5b |
| 2bd•5b |
| 15bc |
| 10b2d |
| 2ac |
| 5b2 |
| 2ac•2d |
| 5b2•2d |
| 4acd |
| 10b2d |
(2)
| 2mn |
| 4m2-9 |
| 2mn |
| (2m+3)(2m-3) |
| 2mn•(2m-3) |
| (2m+3)(2m-3)2 |
| 4m2n-6mn |
| (2m+3)(2m-3)2 |
| 3m |
| 4m2-6m+9 |
| 3m |
| (2m-3)2 |
| 3m•(2m+3) |
| (2m-3)2•(2m+3) |
| 6m2+6m |
| (2m-3)2(2m+3) |
点评:此题考查了通分,通分的关键是确定最简公分母,确定最简公分母要注意:(1)如果各分母的系数都是整数,通常取它们系数的最小公倍数作为最简公分母的系数;(2)如果各分母都是多项式,一般应先将其分解因式再确定最简公分母.
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