初二分式除法
问题描述：
初二分式除法
x^2-4y^2/x^2+2xy+y^2除以x+2y/2x^2+2xy
答
=[(x+2y)(x-2y)/(x+y)(x+y)]/{(x+2y)/[2x(x+y)]}
=(x+2y)(x-2y)(x+y)2x/(x+y)(x+y)(x+2y)
=(2x^2-4xy)/x+y