Question 775582
(1) f ∘ g represents f(g(x)) so let us first substitute g(x) in f(x):

f ∘ g = [1/(1/x)] - 9

(2) Simplify the function. (1 ÷ (1/x) = 1 × x = x)

f ∘ g = x - 9

(3) The function is linear therefore it's domain is R (all real numbers).