6more than 5 times a number (x) is at least twenty–one

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

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A. 127 cm^2 b. 144.5 cm^2 c. 172 cm^2 d. 50 cm^2