yea its about what is represented by them and f g(x)
f (g(x) will be the amount of money he makes per hour for how many gallons he produces...
He makes g(x) gallons per hour and gets f(g(x)) dollars for making that many gallons
f(g(x) = 2(sqrt(3x^3)^2 + 4 is the money he will make for the hours
= 2 (3x^3) + 4
= 6x^3 + 4 per hour
