原式=(2x-y)(x+y)-6x+3y+2x-2y-6
=(2x-y)(x+y)-3(2x-y)+2x-2y-6
=(2x-y)(x+y-3)+2(x+y-3)
=(x+y-3)(2x-y+2)
一道因式分解题 2x²+xy-y²-4x+5y-6
原式=(2x-y)(x+y)-6x+3y+2x-2y-6
=(2x-y)(x+y)-3(2x-y)+2x-2y-6
=(2x-y)(x+y-3)+2(x+y-3)
=(x+y-3)(2x-y+2)