A launched rocket has analtitude, inmeters, given by the polynomial hplus

+vtminus

4.9tsquared

2, where h is theheight, inmeters, from which the launchoccurs, at velocity v in meters persecond, and t is the number of seconds for which the rocket is airborne. If a rocket is launched from the top of a tower 70

70 meters high with an initial upward speed of 20

20 meters persecond, what will its height be after 3

3 seconds?