求2道数学因式分解题.

问题描述:

求2道数学因式分解题.
2x²+xy-y²-4x+5y-6
5+7x-6x²

2x²+xy-y²-4x+5y-6
=(2x-y)(x+y)-4x+5y-6
=(2x-y)(x+y)+2x+2y-6x+3y-6
=(2x-y)(x+y)+2(x+y)-3(2x-y)-6
=[(2x-y)(x+y)+2(x+y)]-[3(2x-y)+6]
=(2x-y+2)(x+y)-3(2x-y+2)
=(2x-y+2)(x+y-3)
5+7x-6x² =(5-3x)(1+2x)