Hello, thank you for taking the time to post your question!
There’s a variety of ways to approach a question like this depending on what type of technology that you have access to! I think the best way to do it is graphically … so you can plot the set of points given and then use a curve fitting tool to line up a quadratic function that hits all of the data points.
When I do that for this one I get y = 3/2x^2 – 6x + 1 for the underlying function. That means that a = 3/2.
I hope that helps get you moving in the right direction!
Feel free to reach out if you have any additional questions beyond that :)
