[(x^3+x^2y)/(x^2y-y^3)]-{[x(x-y)]/(xy+x^2)}-[(2xy)/(x^2-y^2)] 原式=[x^2(x+y)/y(x+y)(x-y))]-[x(x-y)]/[x(y+x)]-[2xy/(x+y)(x-y)]=[x^2/y(x-y)]-(x-y)/(x+y)-2xy/(x+y)(x-y)=[x^2(x+y)-y(x-y)^2-2xy^2]/y(x+y)(x...