因式分解：x^2-2x-2y^2+4x-xy
问题描述：
因式分解：x^2-2x-2y^2+4x-xy
答
4x应该是4y吧.
x²-2x-2y²+4y-xy
=x²-xy-2y²-2x+4y
=(x-2y)(x+y)-2(x-2y)
=(x-2y)(x+y-2)