3/(x-2)-2/(x-1)
=3(x-1)/(x-2)(x-1)-2(x-2)/(x-2)(x-1)
=[3(x-1)-2(x-2)]/(x-2)(x-1)
=(3x-3-2x+4)/(x-2)(x-1)
=(x+1)/(x²-3x+2)若以（x-2）（1-x）为最简公分母的话，答案是不是-（1+x/(x-2)(1-x)）是的但最好把(x-2)(1-x)乘出来 请采纳，谢谢