Question 275891
start with the equation you made


subtracting 38.5 ___ -38.5 = -6(t - 2.5)^2


dividing by -6 ___ 6.417 = (t - 2.5)^2


taking square root ___ ±2.533 = t - 2.5 ___ remember square roots can be positive or negative


adding 2.5 ___ 5.033 = t ___ AND ___ -.033 = t


5 is the answer you are looking for


but the -.033 isn't just junk 
___ it represents the time that the ball would have STARTED from the ground