18/(x²-x)=x²-x-3
(x²-x)²-3(x²-x)-18=0
(x²-x-6)(x²-x+3)=0
(x-3)(x+2)(x²-x+3)=0
∵x²-x+3≠0
∴x=3,x=-2
经检验x=3,x=-2是原方程的解