3x2+2x+1=03 x^{2}+2 x+1=03x2+2x+1=0
3x2−2x−1=03 x^{2}-2 x-1=03x2−2x−1=0
3x2+2x−1=03 x^{2}+2 x-1=03x2+2x−1=0
3x2−2x+1=03 x^{2}-2 x+1=03x2−2x+1=0