已知y-2x=0,求代数式[(x+y)(x-xy+y)]÷[(x+xy+y)(x-y)]的值?

问题描述:

已知y-2x=0,求代数式[(x+y)(x-xy+y)]÷[(x+xy+y)(x-y)]的值?

Y=2X 原式=[(x+4X)(x-2x+4X)]÷[(x+2x+4X)(x-4X)] =[(5X)(3X)]÷[(7X)(-3X)] = -5/7