(x-2x分之x+2 - x-4x+4分之x-1)/x分之x-4
问题描述：
(x-2x分之x+2 - x-4x+4分之x-1)/x分之x-4
答
原式={(x+2)/[x(x-2)]-(x-1)/(x-2)}*x/(x-4) =[(x+2)(x-2)-x(x-1)/[x(x-2)]*x/(x-4) =(x-4-x+x)/[(x-2)(x-4)] =1/(x-2)