[（x×根號x+x×根號y）/（xy-y²）]-[（x+根號下xy+y）/（x×根號x-y×根號y）]
=(x√x+x√y)/(xy-y^2)-[x+√(xy)+y]/(x√x-y√y)
=[x(√x+√y)/[y(√x-√y)(√x+√y)]-[x+√(xy)+y]/{(√x-√y)[x+√(xy)+y]}
=x/[y(√x-√y)]-1/(√x-√y)
=(x-y)/[y(√x-√y)]
=(√x-√y)(√x+√y)/[y(√x-√y)]
=(√x+√y)/y