x/(x-1)-1=3/(x²+x-2)
x/(x-1)-1=3/(x-1)(x+2)
两边同时乘以(x-1)(x+2)得：
x(x+2)-(x-1)(x+2)=3
x²+2x-x²-x+2=3
x=1
此为增根
所以原方程无解.