1/（x-3）-1/(2x+6)-x/(x^2-6x+9)=1/(x-3)-x/(x-3)^2-1/(2x+6)=(x-3)/(x-3)^2-x/(x-3)^2-1/(2x+6)=-3/(x-3)^2-1/(2x+6)=-3(x-3)^2-1/2(x+3)=-6(x+3)/2(x-3)^2(x+3)-(x-3)^2/2(x+3)(x-3)^2=(-x^2-27)/(2x^3-6x^2-18x+...