计算:(x+2)/(x^2 - x - 6) + 2x/(x^2 - 3x) - x/(x^2 - 6x + 9)
问题描述：
计算:(x+2)/(x^2 - x - 6) + 2x/(x^2 - 3x) - x/(x^2 - 6x + 9)
答
(x+2)/(x^2-x-6)+2x/(x^2-3x)-x/(x^2-6x+9)=(x+2)/[(x-3)(x+2)]+2x/[x(x-3)]-x/[(x-3)^2]=1/(x-3)+2/(x-3)-x/[(x-3)^2]=3(x-3)/[(x-3)^2]-x/[(x-3)^2]=(3x-9-x)/[(x-3)^2]=(2x-9)/[(x-3)^2]