Take into account that:
(f ∘ g)(14) = f(g(14))
As you can notice in the table, g(14) = -6, then, f(g(14)) = f(-6), and f(-6) is equal to 13.
Hence, (f ∘ g)(14) = 13
For the other composition of functions, we use the same procedure as before:
(g ∘ f)(3) = g(f(3))
f(3) = -6
g(f(3)) = g(-6) = 15
Hence, (g ∘ f)(3) = 15
(f ∘ f)(−5) = f(f(-5))
f(-5) = 6
f(f(-5) = f(6) = 3
Hence, (f ∘ f)(−5) = 3
(g ∘ g)(−6) = g(g(-6))
g(-6) = 15
g(g(-6)) = g(15) = 14
Hence, (g ∘ g)(−6) = 14