2x^3-3x+1=0
2x³-2x-x+1=0
2x(x²-1)-(x-1)=0
(x-1)[2x(x-1)-1]=0
(x-1)(2x²-2x-1)=0
2(x-1)(x²-x-1/2)=0
2(x-1)[(x-1/2)²-3/4]=0
2(x-1)[x-(1+√3)/2][x-(1-√3)/2]=0
x=1或x=（1+√3）/2或x=1-√3）/2
即：方程2x^3-3x+1=0的根有3个