How can i use this calculator to find a quadratic equation through given points

The general equation for a quadratic is y = a*x² + b*x + c, so if you have 3 points, say (-1, 3), (2, 18) and (5, 69),  you can use the equations section of the calculator to solve for a, b and c as shown in the images below:

I don't think that you can.

Thanks Alan,

I didn't know the calculator could do that.

It is probably not quite what the asker had in mind but it could be and I am glad that you showed me!