find f of g and give domain

Question

suppose f(x)=(3/x+4) and g(x)=(radical x-4) find (f of g)(x) and give its domain

Answer 1

x > 4 domain is any real number greater than or equal to 4

g(x) = sqr(x-4)

f(x) = 3/(x+4)

(fog)(x) = f(g(x)) = 3/(sqr(x-4)+4)