3/(x+1)+3/(x-1)=6/(x²-1)
3/(x+1)+3/(x-1)=6/[(x+1)(x-1)]
去分母,等式两边同乘以(x+1)(x-1)
3(x-1)+3(x+1)=6
6x=6
x=1,代入分式方程检验,x-1=0,分母=0,x=1是方程的增根.
方程无解.