原式=[x(√x+√y)]/[y(x-y)]-[(√x)²+√x×√y+(√y)²]/[(√x)³-(√y)³]=[x(√x+√y)]/[y(√x+√y)(√x-√y)]-[(√x)²+√x×√y+(√y)²]/﹛(√x-√y)[(√x)²+√x×√y+(√y)...