f(x) = 2x-8 and g(x) = sqrt x-5 find (fog)(30)

Answer 1

(f◦g)(x) = f(g(x)) = 2g-8 = 2√(x-5) - 8
so,
(f◦g)(30) = 2√25 - 8 = 2*5 - 8 = 2

or,
f(g(30)) = f(√25) = f(5) = 2*5-8 = 2