因式分解:x^2 - 2xy + y^2 - 3x + 3y - 18 = ()

分类: 作业答案 • 2021-12-19 11:24:40

问题描述：

答

x^2 - 2xy + y^2 - 3x + 3y - 18
=（x^2-2xy+y^2)-3（x-y)-18
=(y-x)^2+3(y-x)-18
设y-x=A
所以原式=A^2+3A-18
=(A-3)(A+6)
=(y-x-3)(y-x+6)

答

x^2 - 2xy + y^2 - 3x + 3y - 18
=(x-y)^2-3(x-y)-18
=(x-y-6)(x-y+3)