Given the height, h , in feet, of the football above the ground after t seconds expressed by h ( t ) = − 8 t^2 + 32 t, the height of the ball on the ground is 0feet.
Substitute h(t) = 0 into the expression and calculate t;
h ( t ) = − 8 t^2 + 32 t
0 = − 8 t^2 + 32 t
8t² = 32t
8t = 32
Divide both sides by 8
8t/8 = 32/8
<em>t = 4s</em>
<em>Hence the football hits the ground after 4seconds</em>
