Question

If a football player passes a football from 4 feet off the ground with an initial velocity of 36 feet per second, how long will it take the football to hit the ground? Use the equation h = −16t2 + 36t + 4.

Answer 1

how long will it take the football to hit the ground?

the ground is at height 0
you should solve for "t" when "h" is 0
\[ 0 = -16t^2 +36t+4\]

Answer 2

I would start by dividing both sides (and *all* terms) by 4 to get
\[ -4 t^2 +9t +1 = 0 \]
use the quadratic formula (or complete the square) to find the value of t