3x²-7xy-6y²-10x+8y+8

3x²-7xy-6y²-10x+8y+8
3x²-7xy-6y²-10x+8y+8

3x²-7xy-6y²-10x+8y+8
3x²-7xy-6y²-10x+8y+8
=(3x+2y)(x-3y)-10x+8y+8 (十字相乘,把-6拆开,然后发现只有这样拆才有-7xy)
=(3x+2y-4)(x-3y-2) (十字相乘,把8拆开,发现只有这样拆才满足-10x,+8y)