Axis is y-axis and vertex is (0, 0).
∴ The parabola is of the form x2 = 4ay and x2 = -4ay.
Since the parabola passes through the point (-1, -3) and it lies in third quadrant the parabola turns downward.
It is of the form x2 = 4ay
but it passes through the point (-1,-3).
∴ (-1)2 = -4a(3).
⇒ 1 = 12a ⇒ a = \(\frac{1}{12}\)
∴ the required equation is x2 = -4. \(\frac{1}{12}\) .y
12x2 + 4y = 0.