Help me solve this please? Functions.?

Question

Also, if you could me a site related to this, thanks.

f(x)= square root of x

and g(x) = 1/9x-4, find (f o g)x?

Answer 1

(f o g)x means do g(x) first then do f of that answer.  Here g(x) is 1/9x - 4 so (f o g)x would be square root of (1/9x - 4)