To solve this problem, first, we use the following form of the equation of a vertical parabola:

where (h,k) are the coordinates of the vertex.
Using the above form and the graph, we get:

Now, to determine the value of a, we consider the point (-2,0) on the parabola:

Solving for a, we get:

Therefore:

Finally, we take the above equation to its standard form:

Answer:
