(6x+1) is all square rooted. I tried to enter alt251 for the square root symbol, but it didn't work.
I am not sure what the question is asking and how to start the problem...
You can learn to use LaTex
The code [tex]f \circ g(x) = \frac{2}{{\sqrt {6x + 1} }}[/tex] gives nice output: $\displaystyle f \circ g(x) = \frac{2}{{\sqrt {6x + 1} }}$.
Let $\displaystyle f (x) = \frac{2}{{\sqrt {x} }}$ and $\displaystyle g(x) = {6x + 1} $.