Afootball is punted from a height of 2.5 feet above the ground with an initial vertical velocity of 45 feet per second. write an equation to model the height h in feet of the ball t seconds after it has been punted. the football is caught at 5.5 feet above the ground. how long was the football in the air?

First assume that the football is going straight up, that is important.  next you have a good rate problem here.  So you have y = mx + b, where m is the rate and b is the starting point.  Now plug in data m is 45 ft/s and b = 2.5ft, so the equation is y = 45x + 2.5.  Now the ball was caught at 5.5 so put that in for y.  5.5 = 45x + 2.5.  Solve to get 1/9 of a sec.