You can put this solution on YOUR website! A kicker starts a football game by "kicking off".
The quadratic function y = -12⋅x2 + 36⋅x models the football's height after x seconds.
How long is the football in the air?
y = -12x^2 + 36x
When the ball hits the ground, y = 0; therefore:
-12x^2 + 36x = 0
Factor out -12x
-12x(x - 3) = 0
x = 0
x = 3 seconds in the air