求x^2-3x/x^2-6x+9*x^2-11x+30/x^2-5x-1
问题描述：
求x^2-3x/x^2-6x+9*x^2-11x+30/x^2-5x-1
答
原式=[x(x-3)/(x-3)²][(x-5)(x-6)/x(x-5)]-1
=[x/(x-3)][(x-6)/x]-1
=(x-6)/(x-3)-1
=(x-6-x+3)/(x-3)
=-3/(x-3)