是不是题目掉了一个立方,应该是4x³吧……4x³-4x²y-xy²+y³=04x²(x-y)-y²(x-y)=0(x-y)(4x²-y²)=0(x-y)(2x-y)(2x+y)=0那么y=x,或y=2x,或y=-2x所以(x²+y²)/xy=1...