1/(x+1)-x/(x^2-1)+(x^2-2x+1)/(3x^2+4x+3)=-1/(x^2-1)+(x-1)^2/(x+1)(3x+1)=1/(x+1)*((x-1)^2/(3x+1)-1/(x-1))=1/(x+1)*(x^2-5x)/(x-1)(3x+1)=x(x-5)/((x+1)(x-1)(3x+1)) 也不知道对不对最后的答案似乎不对一开始那个式子对么？我搞不清题目中哪些是分子，哪些是分母。 1/(x+1)-(x+3)/(x^2-1)*(x^2-2x+1)/(x^2+4x+3)=1/(x+1)-(x+3)/[(x+1)(x-1)]*(x-1)^2/[(x+3)(x+1)]=1/(x+1)-(x-1)/(x+1)^2=[(x+1)-(x-1)]/(x+1)^2=2/(x+1)^2 希望这次对了