You can put this solution on YOUR website!
First set it up like it says.
then subtract the 80 from both sides.
then divide the whole thing by -16.
then you simply factor and solve
t=5 or t=1
Now these answers are when the rocket hit 80 feet on its way up and way down.
So the answer would be 5 seconds because it takes longer to come down.
Hope that helps!