Quadratic Word Problem

By Andrew Braden and Grace Naranjo

Problem:

The entrance to an athletic field is in the shape of a parabolic archway. The archway is modeled by the equation d=12x-x^2, where d represents the distance in feet that the arch is above the ground for any x value.

Question A

For what values of x will the arch be 20 feet above the ground?

Question B

What is the max height of the arch above the ground?