一元三次方程x^3-3x^2+2求解!要過程

一元三次方程x^3-3x^2+2求解!要過程

答:
x^3-3x^2+2
=(x^3-x^2)-2(x^2-1)
=(x-1)x^2-2(x-1)(x+1)
=(x-1)(x^2-2x-2)
所以:
x^3-3x^2+2=0
(x-1)(x^2-2x-2)=0
解得:x=1或者x^2-2x+1=3
解得:x=1或者x=1+√3或者x=1-√3