Question

Which of the following is always true?

A.
f (g(x)) = g( f (x))

B.
f ( f (x)) = ( f (x))2

C.
f (g(x)) = f (x) • g(x)

D.
f (g(x)) = ( f o g)(x)

Answer 1

It's the last one

these are 2 ways of writing the function 'f of g(x)'.