Question

25 points for who ever helps me with this

Answer 1

5 seconds

Explanation:

h = -16t^2 +64t +80

We want to know when it hits the ground or when h=0

0 = -16t^2 +64t +80

Factor out -16

0 = -16 (t^2 -4t -5)

We can factor inside the parentheses

0 = -16 (t-5) (t+1)

Using the zero product property

t-5 = 0 t+1 =0

t =5 t=-1

Time cannot be negative, so t =5 seconds