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.

0 = -16t² + 36t + 4 
0 = -8t² + 18t + 2 ← Complete the square to solve 
-8(t² - 9t/2) = -2 
8(t² - 9t/4 + 81/64) = 2 + 81/8 
8(t - 9/8)² = 97/8 
(t - 9/8)² = 97/64 
t - (t = 0) 
 (h = 0) at: 
t = (9 + √97)/8 ≅ 2.356 seconds