Can someone get me started on this problem please, "The height of an object thrown upward with an initial velocity of 64 feet per second is given by the formula h=-16t^2 +64t, where t is the time in seconds. How long will it take the object to reach a height of 64 feet?" Thanks.

Question

anonymous · Answer

The problem gives you:
h=-16t^2+64t+80
where
h is height in feet
t is time in secs

anonymous · Answer

If it hits the ground, h = 0 so 
set h=0 and solve for t: 
h=-16t^2+64t+80
0=-16t^2+64t+80
0=-4t^2+16t+5

anonymous · Answer

Solving using the quadratic equation yields:
t = {-0.29, 4.29}

anonymous · Answer

We can throw out the negative solution leaving
t = 4.29 seconds :)

anonymous · Answer

medal plz :]

anonymous · Answer

no, where are you getting 80?