Please help me figure this out?

Question

state the domain of [fog][x] for the following:

f(x)= ((1)/(x))

g(x)=7-x

Answer 1

(f o g)(x)

= (f (g(x)) )

= 1 / (7 - x).

f o g is valid everywhere except x = 7, as this makes the denominator 0.

Domain: (- infty, 7) U (7, infty).