I'm assuming you're solving for x in these?
The first one is rather troublesome if you are, since you have an x in the exponents.
The second one is very straight-forward. Start out by swapping the two sides (so x is on the left side), and then isolate x as normal.
--If you are solving this equation for y, it's important to remember that every positive number has two square roots, one positive and one negative, and that taking the square root of both sides applies to the whole side, so you'd end up with two answers. One would look like the third example, and the other would be the negative of that.
With the third and fourth, you don't have to worry about that, because while every positive number has two square roots, there's only one answer you can get by squaring (or cubing) a given number. Square (or cube) both sides to get rid of the root symbol, then isolate x.