1/(x*x-2x-3)+2/(x*x-x-6)+3/(x*x+3x+2)=1/(x-3)*(x+1)+2/(x-3)*(x+2)+3/(x+1)*(x+2)=[(x+2)+2(x+1)+3(x-3)]/(x+1)(x+2)(x-3)=(6x-5)/(x+1)(x+2)(x-3),因为分母不能为零 所以6x-5=0 x=5/6