Please help me solve

A student fires a cannonball horizontally with a speed of 21.0m/s from a height of 55.0m. Neglect drag. horizontal (x) vertical (y) m/s Vo O m/s > m/s > unit m/s Vf unit AX = unit AV = m unit unit 11 O m/s2 11 unit . v How long did the ball remain in the air? unit > How far from from the building will the ball land (measured along the ground)? unit >