x2+y2+4x−2y−20=0x^{2}+y^{2}+4 x-2 y-20=0x2+y2+4x−2y−20=0
x2+y2+4x+2y−20=0x^{2}+y^{2}+4 x+2 y-20=0x2+y2+4x+2y−20=0
x2+y2−4x+2y−20=0x^{2}+y^{2}-4 x+2 y-20=0x2+y2−4x+2y−20=0
x2+y2−4x−2y+20=0x^{2}+y^{2}-4 x-2 y+20=0x2+y2−4x−2y+20=0