用双十字相乘法分解因式:  (1)x2-8xy+15y2+2x-4y-3;   (2)x2-xy+2x+y-3;

问题描述:

用双十字相乘法分解因式:  (1)x2-8xy+15y2+2x-4y-3;   (2)x2-xy+2x+y-3;

x2-8xy+15y2+2x-4y-3;=(x-3y)(x-5y)+2x-4y-3x-3y-1x-5y3x2-8xy+15y2+2x-4y-3=(x-3y-1)(x-5y+3)(2)x2-xy+2x+y-3=(x+2y)(x-y)+2x+y-3x+2y 3x-y-1x2-xy+2x+y-3=(x+2y+3)(x-y-1)两道题双十字相乘法的图x2-8xy+15y2+2x-4y-3;1 -31-5=(x-3y)(x-5y)+2x-4y-3x-3y-1x-5y3x2-8xy+15y2+2x-4y-3=(x-3y-1)(x-5y+3)(2)x2-xy+2x+y-31 21-1=(x+2y)(x-y)+2x+y-3x+2y 3x-y-1x2-xy+2x+y-3=(x+2y+3)(x-y-1)