【1-2x/(x+y)】÷(x^2-2xy+y^2)/(3x+3y)+(x^2+xy)/(x^2-y^2)
=(x+y-2x)/(x+y)÷(x-y)^2/3(x+y)+x(x+y)/(x+y)(x-y)
=[-(x-y)/(x+y)]÷[(x-y)^2/3(x+y)]+x/(x-y)
=-3/(x-y)+x/(x-y)
=(x-3)/(x-y)
=(1-3)/(1+√3)
=-2/(1+√3)
=-2(1-√3)/[(1+√3)(1-√3)]
=1-√3