[-GS-]

Sorry guys, i know this isnt a homework forum or anythign, but i really need help with this thing.

Aite well just saying that i had an equation that was

h = height
t = time

h=-4.9t²+22.8t

1)How would i go about finding when the ball was at its maximum height?
2)And how would i go about finding out how long it was in the air for?