An airplane travels 330 m down the runway before taking off. assuming that it has constant acceleration, if it starts from rest and becomes airborne in 9.00 s, how fast (in m/s) is it moving

Under constant acceleration, we have average velocity over a time interval of duration satisfying

where are the plane's initial position and velocity (respectively) and are the plane's position and velocity (respectively) after 9.00 seconds. So