问题描述: 数学题: (x+2y分之3x-x-2y分之x)÷x2-4分之x,其中x=-3;(a-b分之a+b+b-a分之b)÷a+b分之1,其中a=2分之1,b=3分之1 1个回答 分类: 综合 2014-10-06 问题解答: 我来补答 原式=[3x(x-2y)-x(x+2y)]/(x+2y)(x-2y)×(x+2y)(x-2y)/x=3(x-2y)-(x+2y)=2x-8y请检查题目原式=[(a+b)/(a-b)-b/(a-b)]×(a+b)=a/(a-b)×(a+b) 再问: �ĺ��� 再答: ԭʽ=[3x(x-2)-x(x+2)]/(x+2)(x-2)��(x+2)(x-2)/x =3(x-2)-(x+2) =2x-8 �� x=-3ʱ ԭʽ=-6-8=-14 ԭʽ=[(a+b)/(a-b)-b/(a-b)]��(a+b) =a/(a-b)��(a+b) =a(a+b)/(a-b) =1/2(1/2+1/3)/(1/2-1/3) =5/2 展开全文阅读