Question

The function h(t)=-4t^2+14t+8 gives the height h, in feet, of a football as a function of time t, in seconds, after it is kicked. How long does it take for the football to hit the ground?

Answer 1

t = 4

Explanation:

Use the quadratic formula to find the zeros of the function, when h(t) equals 0 that means the ball is touching the ground, giving the maximum time it took for the ball to hit the ground.

`(-b(+)/(-) √(b^2-4*a*c) )/(2*a) \\(-14(+)/(-) √(14^2-4*-4*8) )/(2*-4) \\t = -0.5,4`

It takes 4 seconds, since time can not be negative