[(2/a-2b)+(1/a-b)]*[(a-2b)/(3a^2-ab-4b^2)]
问题描述：
[(2/a-2b)+(1/a-b)]*[(a-2b)/(3a^2-ab-4b^2)]
4x-2/x^2-x-2+(1-1/x+1)/x/x-1
答
通分,再乘,得1/(a^2-b^2)4x-2/x^2-x-2+(1-1/x+1)/x/x-1是不是少打了括号4x-2/（x^2-x-2）+(1-1/x+1)/x/x-1yes4x-2分之x^2-x-2汗~~是 x^2-x-2分之4x-2不知道对不对。。。4x/(x+1)(x-2)