x2−8x−18=0x^{2}-8 x-18=0x2−8x−18=0
x2−8x+18=0x^{2}-8 x+18=0x2−8x+18=0
x2−8x+16=0x^{2}-8 x+16=0x2−8x+16=0
x2−8x−16=0x^{2}-8 x-16=0x2−8x−16=0