Question 758201
Suppose a football is kicked from the ground and its height in feet above the ground is given by h = -3.9t2 + 15.6t. The height above the ground is "h". The time in seconds, after the ball is kicked, is "t". How long is the ball in the air?
-----
Solve -3.9t^2 + 15.6t = 0
-3.5t(t - 4) = 0
Positive solution:
t = 4
-----
In the air for 4 seconds.
Cheers,
Stan H.
==========================