Question

几道因式分解·分组分解法 1，x^3+x²y-xy²-y^3 2，xz-yz-x²+2xy-y²

选择题：多项式xy+ax+by+c可分解为两个一次因式（x+m)(x+n)的乘积，则（）
A，ab=c B，ac=b C，a=b=c D，a=b+c

Answer 1

x^3+x²y-xy²-y^3
=x^3-y^3+x²y-xy²
=(x-y)(x²+xy+y²)+xy(x-y)
=(x-y)(x²+2xy+y²)
=(x-y)(x+y)²

xz-yz-x²+2xy-y²
=z(x-y)-(x-y)²
=(x-y)(z-x+y)

3 题目错了 如果后面是（x+m)(y+n)的话 选A

Answer 2

1。(x-y)(x+y)^2
2.(x-y)(z-x+y)
3.A