PLEASE HELP me

Question

The path of a ball being thrown off a building can be modeled by the equation  

How long does it take to get to its maximum height?

What is an appropriate domain and range for this function?

What does the 80 in the equation represent?

Answer 1

max height is when y' = 0 = -32t +64

t = 64/32 = 2 seconds to reach maximum height

max height = -16(2)^2 + 64(2) + 80 = 64+80 = 144 feet

domain is 0<x<5 seconds

range is 0<y<144 feet

80 represents the initial height