(x+m)/(x-1)-x/(x+1)=0
两边乘(x+1)(x-1)
(x+m)(x+1)-x(x-1)=0
增根即公分母为0
所以(x+1)(x-1)=0
x=1,x=-1
x=1,代入(x+m)(x+1)-x(x-1)=0,(m+1)(1+1)-0=0,m=-1
x=-1,代入(x+m)(x+1)-x(x-1)=0,0+1*(-2)=0,不成了
所以m=-1