x³-3x²+2=0
x³-x²-(2x²-2)=0
x²(x-1)-2(x+1)(x-1)=0
(x-1)(x²-2x-2)=0
x-1=0 或x²-2x-2=0
x=1或x²-2x+1=3
(x-1)²=3
x-1=±√3
于是
x1=1+√3 x2=1-√3 x3=1