The equation for a parabola is y=ax^2+bx+c. We are given two points, and the axis of symmetry (x=12) which will be plenty for us.

The axis of symmetry can be found with the equation -b/2a=12. Solving for b, we get -b=24a, so **b=-24a**. Now we can turn our equation into:

y=ax^2-24ax+c. We can plug in the two points to get the two equations

-4=-144a+c

0=585a+c

Solving the system of linear equations, **a=4/729 and c=-260/81.** Now we can solve for **b=-96/729.**

Finding the other root of the quadratic 4/729x^2-96/729x-260/81=0, we get the other x-intercept to be **(39, 0) or 39.**