x2+y2−2x−2y−8=0x^{2}+y^{2}-2 x-2 y-8=0x2+y2−2x−2y−8=0
x2+y2−2x−y−12=0x^{2}+y^{2}-2 x-y-12=0x2+y2−2x−y−12=0
x2+y2+2x−y−12=0x^{2}+y^{2}+2 x-y-12=0x2+y2+2x−y−12=0
x2+y2+2x−2y+8=0x^{2}+y^{2}+2 x-2 y+8=0x2+y2+2x−2y+8=0