因式分解x^2-2xy-8y^2
问题描述：
因式分解x^2-2xy-8y^2
答
x^2-2xy-8y^2
=x^2-2xy+y^2-9y^2
=(x-y)^2-(3y)^2
=(x-y+3y)(x-y-3y)
=(x+2y)(x-4y)
答
原式=x^2-4xy+2xy-8y^2
=x(x-4y)+2y(x-4y)
=(x-4y)(x+2y)