还有两道
x²-(a+b)xy+aby²
6x²+xy-2y²
X²+4X-12
=(x-6)(x+2)
=(x-ay)(x-by)
=(2x-y)(x+2y)
X²+4X-12=(x+6)(x-2)
x²-(a+b)xy+aby²=(x-ay)(x-by)
6x²+xy-2y²=(2x-y(3x+2y)