Focus (-3,3) vertex (0,3). What is the equation for the parabla

(y - 3)² = 12(x + 3)  

Step-by-step explanation:

The focus is to the right of the vertex, so the parabola is sideways and opens to the right.

The conic form of a sideways parabola is

(y - k)² = 4p(x - h)

The vertex is at h = -3; k = 3

The focus is at (h + p, k) = (-3 + p, 3)

The vertex and focus are three units apart, so p = 3.

The equation of your parabola is

(y - 3)² = 12(x + 3)

The figure below shows the graph of your parabola with its focus and vertex.