How would you go about solving this?

The question says: "Select the expression that is equivalent to."

And I'm sure the answer is 3^4. But how would you manage to get this answer?

I read something about, but what would you need to do when there's no "n" there? Is it as simple as n being 2 by default?

Here's a clear explanation:

First, remember that there's always an invisible 2 before the √ in a square root. You just don't see it because it makes no difference. If we wanted the cube root, there would be a 3 before the √.

So, basically, the 'n' in this case is a 2. 8 / 2 = 4.

I hope you understand me, or else, message me for further explanation.

No problem.

:D