The graph of a linear function is shown in the coordinates plane. What is the rate of Change in y per unit change in x for this linear function

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