Answer:
(gof)(6) = 334
Explanation:
The expression "(gof)(6)" means a composite function. Putting one function into another and then evaluating.
Thus,
(gof)(6) means "Put the function f into g and get a new function (gof)(x). Then put 6 into x of that new function and thus we get (gof)(6)"
So, let's find (gof)(x) first. Shown below:

Now, we simplify:

Now, we plug in 6 into x and evaluate:

Thus, the value is 334