考点:通分
专题:
分析:找出最简公分母是解决问题的关键,答题时首先找出两式的最简公分母,然后进行通分.
解答:解:(1),- 由原式可得最简公分母是:a2b2, 故通分可得出:=-,-=-;
(2),,; 由原式可得最简公分母是:12x3yz2, 故通分可得出:=,=,=;
(3),; 由原式可得最简公分母是:(x+y)(x-y), 故通分可得出:=,=; |
| |
(4),; 由原式可得最简公分母是:x(x+y)(x-y), 故通分可得出:=,=;
(5), 由原式可得最简公分母是:x(x+1)2, 故通分可得出:=,=; (6),, 由原式可得最简公分母是:2x(x-3)(x+3), 故通分可得出:=2(x+1)(x+3)(x-3) | 2x(x+3)(x-3) | ,=,=; | | |
(7),; 由原式可得最简公分母是:(2m+3)(2m-3), 故通分可得出:=,=;
(8),; 由原式可得最简公分母是:(a+1)2(a-1), 故通分可得出:=,=;
(9), 由原式可得最简公分母是:(a-b)2, 故通分可得出:=,=; | | |
(10)a-3,; 由原式可得最简公分母是:a+3, 故通分可得出:a-3=,;
(11),; 由原式可得最简公分母是:ab(b+1), 故通分可得出:=,=;
(12),,; ∵==,
∴可得最简公分母是:(x-2)(x+2)(x-3)(x+3), 故通分可得出:=(x-3)(x+3) | (x-2)(x+2)(x-3)(x+3) | , =-x(x-2)(x-3) | (x-2)(x+2)(x+3)(x-3) | ,=(x-3)(x-2)(x+3) | (x-2)(x+2)(x-3)(x+3) | ; | | |
(13),; 由原式可得最简公分母是:(2a+1)(2a-1)2, 故通分可得出:=,=4(2a-1)(2a+1) | (2a-1)2(2a+1) | ; | | |
(14)
,
;
由原式可得最简公分母是:2(a-1)(a+3),
故通分可得出:
=
=
,
=-
=-
;
(15)
,
,
.
由原式可得最简公分母是:(2a+b)(2a-b),
故通分可得出:
=
,
=
,
=
.
点评:此题主要考查了通分,通分时若各分式的分母还能分解因式,一定要分解因式,然后再去找各分母的最简公分母,最简公分母的系数为各分母系数的最小公倍数,因式为各分母中相同因式的最高次幂,各分母中不相同的因式都要作为最简公分母中的因式,要防止遗漏因式.