(7x-x^2)/(x^2-8x+7)-(4x^2+4x+1)/(1-4x^2)
问题描述：
(7x-x^2)/(x^2-8x+7)-(4x^2+4x+1)/(1-4x^2)
答
(7x-x^2)/(x^2-8x+7)-(4x^2+4x+1)/(1-4x^2)=-x(x-7)/(x-7)(x-1）-(2x+1）^2/(1-2x)(1+2x)=-x/(x-1)-(2x+1)/(1-2x)=-x/(x-1)+(2x+1)/(2x-1)=[-x(2x-1)+(x-1)(2x+1)]/(2x-1)(x-1)=[-2x^2+x+2x^2+x-2x-1]/(2x-1)(x-1)=-...