Which is the equation of a parabola with Vertex (0, 0) and focus (-3, 0)?

-12x = y^2

Step-by-step explanation:

Notice that the vertex and the focus are both located on the horizontal line y = 0 (that is, on the x-axis).

Because the focus is to the left of the vertex, we know that the parabola opens left.

The distance between focus and vertex is 3 units.

We'll adapt this equation:  4px = y^2.  Here p is -3:

                                         4(-3)x = y^2, or

-12x = y^2