Respuesta :

Answer:If you use quadratic formula the answer is (rounded) 2.88s

Step-by-step explanation:

Answer:

2.882491 seconds

Step-by-step explanation:

H=156-8t-16t²

-16t²-8t+156=0

16t²+8t-156=0

4t²+2t-39=0

t=2.882491 seconds ................