分解因式:3x2+5xy-2y2+x+9y-4.

问题描述:

分解因式:3x2+5xy-2y2+x+9y-4.

3x2+5xy-2y2+x+9y-4
=(3x-y)(x+2y)+x+9y-4
=(3x-y)(x+2y)-(3x-y)+4x+8y-4
=(3x-y)(x+2y-1)+4(x+2y-1)
=(3x-y+4)(x+2y-1).