【急】 分式加减
问题描述：
【急】 分式加减
[(a-b)/(a+b-(a+b)/(a-b)]/[1-(a^2+b^2)/(a^2-2ab+b^2)]
[x-x/(x+1)]*[(x+1)/(x^+3x+2)]÷[(x^2-2x)/(x^2-4)]
x/(x+1)-(x+3)/(x-1)÷(x^2-2x+1)/(x^2+4x+3)
b^2/(a+b)÷[a/(a-b)-1]÷[a-a^2/(a+b)]
[(3x-3y)/(y^2-x^2)]+[(x^2-2xy+y^2)/(x^2-y^2)}-[(x^2-x-6)/(x+2)]÷(x+y)
答
[(a-b)/(a+b)-(a+b)/(a-b)]/[1-(a^2+b^2)/(a^2-2ab+b^2)]=[(a-b)^2/(a^2-b^2)-(a+b)^2/(a^2-b^2)]/[1-(a^2+b^2)/(a-b)^2]=[(a-b)^2-(a+b)^2]/[(a^2-b^2)]/[1-(a^2+b^2)/(a-b)^2]=[(a-b+a+b)(a-b-a-b)]/[(a^2-b^2)]/[...