-50= 6a+28 please help

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

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

Which is a graph of a proportional relationship?