Question

Tanya kicks a ball into the air. The function that models this scenario is f(t) = –16t2 + 96t, where h is the height of the ball in feet and t is the time seconds. When will the ball hit the ground?

Answer 1

Assuming that is t^2 which I think it is,
You do 16t^2-96t=0
16t(t-6) - factoring
t=6 
because t>0

Answer 2

The ball will hit the ground when h(t)=0 so:

16t^2-96t=0

16t(t-6)=0, since t>0

t=6

So the ball with hit the ground after 6 seconds.