去分母，得(x+1)^2-4=x^2-1x=1经检验x=1是增根，原方程无解。
(x+1)/(x-1)-4/(x^2-1)=11-2/(x-1)-[2/(x-1)-2/(x+1)]=1-4/(x-1)=-2/(x+1)2x-2=4x+42x=-6x=-3
