Please help my assignment

Monica build a remote control toy airplane for science project to test the plane she launched it from the top of a building the plane travel a horizontal distance of 50 feet before landing on the ground a quadratic function which models the height of the plane in feet relative to the ground at a horizontal distance of x feet from the building is shown

Solve for x and select the correct answer

A11 gram sample of a substance that’s used to treat thyroid disorders has a k-value of 0.1247