3次方分解不了
只能是2次方
^2-3xy-10y^2+x+9y-2
=(x+2y)(x-5y)+2x+4y-x+5y-2
=(x+2y)(x-5y)+2(x+2y)-(x-5y+2)
=(x+2y)(x-5y+2)-(x-5y+2)
=(x+2y-1)(x-5y+2)那么就是老师题出错了。谢谢!请点击左下角的“采纳为满意答案”，祝学习进步！