Answer:
in steps
Step-by-step explanation:
ground height = 0
(are you sure your formula is correct? isn't it - 16t²?)
if h=16t² +64t+192 is true then
16t² +64t+192 = 0
t² + 4t + 12 = 0
t = (-4 ± √(4² - 4*12)) / 2*1 = (-4 ± √-32) / 2 = -2 ± 2√-2
There is no solution of t
if it is h= - 16t² +64t+192
0 =- 16t² + 64t + 192
t² - 4t - 12 = 0
(t + 2) (t -6) = 0
t should be positive
t = 6 sec
