Question 122238
well all you have to do here is plug 9 in for h(t) and solve for t.<br>

9 = 1 + 13t -5t^2 ---> Combine like terms
5t^2-13t+8 = 0 ---> factor
(5t-8)(t-1)=0<br> --->set each factor to zero and solve

5t-8=0 ---> add 8 to both sides
5t = 8 ---> divide both sides by 5
t = 8/5<br>

t-1 = 0 --> add 1 to both sides
t = 1<br>

so the ball reaches the height of 9 meters 1 second after it was hit.