2/(x^2-1)-1/(x-1)=1
2/(x+1)(x-1)-1/(x-1)=1 两边乘(x+1)(x-1)
2-（x+1）=x^2-1
x^2+x-2=0
(x+2)(x-1)=0
x1=-2 x2=1(舍)