Question 1083628
The equation is f(t)=-16t^2+150t+2
It hits the ground when f(t)=0
factor out a -2 and divide both sides by it.
8t^2-75t-1=0
t=(1/16)(75+/- sqrt (5625+32);sqrt 5657=75.21
use positive root only t=150.21/16=9.4 sec
Check  by finding vertex t value which should be close (started +2 feet, so won't be exact) to half the entire time, since the vertex is the axis of symmetry.
t=-b/2a at vertex=-150/-32=4.7 sec.
Check again by graphing.
{{{graph(300,300,-10,15,-20,400,-16x^2+150x+2)}}}