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: