4x2+2x+1=04 x^{2}+2 x+1=04x2+2x+1=0
4x2−2x+1=04 x^{2}-2 x+1=04x2−2x+1=0
2x2−4x+1=02 x^{2}-4 x+1=02x2−4x+1=0
2x2+4x+1=02 x^{2}+4 x+1=02x2+4x+1=0