To solve this equation, simply plug in the value of h = 0 feet, as this would be the height the object will be on the ground. It would be 0.
Afterwards, solve the equation by factoring the quadratic function.
16t^2 - 64t - 80 = 0.
8(2t^2 - 8t - 10) = 0
2t^2 - 10t + 2t - 10 = 0
2t(t - 5) + 2(t - 5) = 0
(2t + 2)(t - 5) = 0
T = 5 and t = -1.
Since time can’t be negative, there is only one solution, t = 5.
It would be about 5 seconds.