Given that y=f(g(x)) this implies that y is formed by composition of the function of the functions f(x) and g(x) given by f ο g (x).
thus:
y=f(g(x))=3/(sqrt 3x)+4
breaking down the above it implies that the functions f(x) and g(x) will be:
f(x)=x+4
g(x)=3/(sqrt 3x)