Jason hits a volleyball with an initial velocity of 6 meters per second straight up. if the back starts at 2 meters above the floor how long will the ball be in the air

Vi = 6 m/s 
d = -2 m 
a = - 9.81 m/s^2 
t = ? 
Formula 
d = vi*t + 1/2 a t^2 
- 2 = 6m/s *t - .5 * 9.81 * t^2 
Put the - 2 on the right. 
4.905 t^2 + 6 m/s t +2 = 0 
 a = -4.905 m/s^2 
b = 6 m/s 
c = 2 m 
t = [- b +/- square root(b^2 - 4ac)]/(2a) 
t = [ -6 +/- square root (6^2 - 4*(-4.905)*2)] / (- 4.905*2) 
t = [-6 +/- 8.674) / - 9.81 
t = -14.674/-9.81 
t = 1.69 seconds.