1. A model rocket is launched from the roof of a building. Its flight path through the
 air is modeled byn = -312 + 120 + 36, where h is the height of the rocket above the
 ground in meters and tis the time after the launch in seconds.
 a) What is the height of the building?
 b) How long does it take for the rocket to hit the ground?
 c) At what time does the rocket reach maximum height? What is the maximum
 height?
 d) For how long does the rocket have a height of 45m or greater?