x^2-2xy+y^2-5x+5y-6
=(x^2-2xy+y^2)-5(x-y)-6
=(x-y)^2-5(x-y)-6
=[(x-y)-6][(x-y)+1]
=(x-y-6)(x-y+1)
你说的这个Z+Z超级画板没用过,你可以看看网上的资料