x2+y2+6x+2y−7=0x^{2}+y^{2}+6 x+2 y-7=0x2+y2+6x+2y−7=0
x2+y2−6x−2y−7=0x^{2}+y^{2}-6 x-2 y-7=0x2+y2−6x−2y−7=0
x2+y2+6x−2y+7=0x^{2}+y^{2}+6 x-2 y+7=0x2+y2+6x−2y+7=0
x2+y2−6x+2y+7=0x^{2}+y^{2}-6 x+2 y+7=0x2+y2−6x+2y+7=0