A circle with equation x2+y2+2x=0x^2 + y^2 + 2x = 0x2+y2+2x=0 has its center at:
(0,0)(0, 0)(0,0)
(−1,0)(-1, 0)(−1,0)
(1,0)(1, 0)(1,0)
(0,−1)(0, -1)(0,−1)