2X的平方减2X减1=3x²-（x²+2x+1）=3x²-（x+1）²=（√3x+x+1）（√3x-x-1）=[(√3+1)x+1][(√3-1)x-1]
2x^2-2x-1=[x-(1+√3)/2][x-(1-√3)/2]
