alexis bumps a volleyball from 4 ft high with an initial velocity of 20 ft/s.
Find the x-intercept
Write in vertex form
Identify domain and range
if she bumps it straight up, it's not very useful, unless it's a set-up.
If you want the height as a function of time,
y = 4 + 20t - 16t^2 = -16(t - 5/8)^2 + 41/4
plot the graph, and the domain and range should be clear.