Question 1205920
A ball is thrown upward from the top of a building 80 feet tall with an initial velocity of 64 feet per second.
 Solve the equation: -16t^2+64t+80=144 to find the time t​ (in seconds) at which the ball is 144 feet from the ground. 
:
 -16t^2 + 64t + 80 = 144
Simplify, divide equation by -16
t^2 - 4t - 5 = -9
t^2 - 4t - 5 + 9 = 0
t^2 - 4t + 4 = 0
Factors to
(t-2)(t-2) =  0
t = 2 Seconds