题如下、 已知2x+y=0,求x2+xy分之x-2y乘以(x2-y2)除以
问题描述：
题如下、 已知2x+y=0,求x2+xy分之x-2y乘以(x2-y2)除以
x分之x2-4xy+4y2的值.
求（X2+XY）分之（X-2Y）乘以（X2-Y2）除以（X）分之（X2-4XY+4Y2）的值
答
{[(x-2y)/(x^2+xy)]/(x^2-y^2)}*/[(x^2-4xy+4y^2)/x]
=x(x-2y)/[(x^2+xy)(x^2-y^2))(x^2-4xy+4y^2)]
=x(x-2y)/[x(x+y)(x-y)(x+y)(x-2y)^2]
=1/[(x-y)(x+2y)(x+y)^2]