2x³-6x²+4=0
（2x³-2x²)-4x²+4=0
2x²(x-1)-4(x²-1)=0
2x²(x-1)-4(x+1)(x-1)=0
(x-1)(2x²-4x-4)=0
2(x-1)(x²-2x-2)=0
(x-1)[(x-1)²-3]=0
(x-1)(x-1-√3)(x-1+√3)=0
x=1,x=1+√3,x=1-√3