2x2+xy-y2-4x+5y-6怎么算,thanks
问题描述：
2x2+xy-y2-4x+5y-6怎么算,thanks
答
大十字相乘法因式分解
2x-y 2
x+y -3
∴2x^2+xy-y^2-4x+5y-6=(2x-y+2)(x+y-3)
答
2x^2+xy-y^2-4x+5y-6
=（x+y）(2x-y)-4x+5y-6
=（x+y）(2x-y)+2(x+y)-6x+3y-6
=(x+y)(2x-y+2)-3(2x-y+2)
=(2x-y+2)(x+y-3)