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