Help Please!

Can someone help me out with this problem:
A ball is thrown up at the edge of a 274 foot cliff. The ball is thrown up with an initial velocity of 72 feet per second.
Its height measured in feet is given in terms of time t, measured in seconds by the equation h= -16t^2 + 72t + 274
a. How high will the ball go and how long does it takes to reach that height?
____feet , ___seconds
b. How long does it take the ball to come back to the ground ?
___ seconds

a) Find the axis of symmetry for the parabolic height function...the maximum will occur there.

b) Set and use the positive root.

Thanks a bunch, got it right away when I read your comment.