a bullet is fired into the air with an initial upward velocity of 64 fps from the top of a building 80 feet high. The equation that gives the height of the bullet at any time (t), is h=80+64t-16t^2. Find the times at which the arrow will be 128 feet in the air? This talks about a bullet but asks about an arrow, how do I answer this for the arrow?

4 answers

My post was rejected.
t^2-4t-5=-8
t^2-4t-5=-8

(t-1)(t-3)=0
Step 1: h = -16t^2+64t+80=128.