SOLVED: An amusement park is building a roller coaster with a drop section modeled by a quadratic. The roller coaster will dip 9 feet below ground level. The roller coaster will dip below ground level at a horizontal distance of 42 feet from the peak re-emerge to ground level at a horizontal distance of 78 feet from the peak. What is the expression that models this scenario? (use the peak of the roller coaster, just before the drop section, as your Y intercept)