f(g(x)) is equal to 6x - 14.
In order to find any composite function, we need to take the instead function (g(x)) and plug it into the outside function (f(x)) where the x term is. So start with the f(x).
f(x) = 3x + 1
Now stick g(x) where x is.
f(g(x)) = 3(2x - 5) + 1
Distribute
f(g(x)) = 3x -15 + 1
And then simplify.
f(g(x)) = 3x - 14
