因式分解 x²+xy-2y²-x+7y-6
问题描述：
因式分解 x²+xy-2y²-x+7y-6
答
x²+xy-2y²-x+7y-6
解（x+2y)(x-y)-x+7y+2×(-3)
=(x+2y-3)(x-y+2)
答
x²+xy-2y²-x+7y-6
＝（x+2y)(x-y)-x+7y+2*(-3)
=(x+2y-3)(x-y+2)