Answer:
10 meters
Step-by-step explanation:
The given function [tex]h(t)=-2t^2+8t+10[/tex] represents the height, [tex]h[/tex], in meters, [tex]t[/tex] seconds after the ball is thrown.
Since the ball is thrown off the roof, then ball's height will be equal to the roof's height before being thrown (0 seconds). Therefore, substitute [tex]t=0[/tex] into the given function [tex]h(t)=-2t^2+8t+10[/tex]:
[tex]h(0)=-2(0^2)+8(0)+10,\\h(0)=0+0+10,\\h(0)=\boxed{10\text{ meters}}[/tex]
Therefore, the building is 10 meters tall.