x2−4x+8=0x^{2}-4 x+8=0x2−4x+8=0
x2−4x−8=0x^{2}-4 x-8=0x2−4x−8=0
x2+4x−8=0x^{2}+4 x-8=0x2+4x−8=0
x2−8x+4=0x^{2}-8 x+4=0x2−8x+4=0