x2+y2+6x−8y+16=0x^{2}+y^{2}+6 x-8 y+16=0x2+y2+6x−8y+16=0
x2+y2−6x+8y−16=0x^{2}+y^{2}-6 x+8 y-16=0x2+y2−6x+8y−16=0
x2+y2−6x+8y+16=0x^{2}+y^{2}-6 x+8 y+16=0x2+y2−6x+8y+16=0
x2+y2−6x−8y+16=0x^{2}+y^{2}-6 x-8 y+16=0x2+y2−6x−8y+16=0