因式分解拆项法x^3+2x-3x^3-8

问题描述:

因式分解拆项法
x^3+2x-3
x^3-8

x^3+2x-3
=x^3-x^2+x^2+2x-3
=x^2(x-1)+(x-1)(x+3)
=(x-1)(x^2+x+3)
x^3-8
=(x-2)(x^2+2x+4)

x^3+2x-3=x^3-x^2+x^2+2x-3=x^2(x-1)+(x-1)(x+3)=(x-1)(x^2+x+3)
x^3-8 =(x-2)(x^2+2x+4)