Zero exponents are simple. They follow one single rule that applies wherever you will see them. No matter what the base is, if it is as simple as x, or as complicated as (45xyz / (412ab+26c)), if you raise the base to a power of zero, the expression equals 1.
a0 = 1
It is a very handy shortcut, so whenever you see it, you can make life a lot easier for yourself if you just simplify the expression to 1. For example, you don't want to get stuck rearranging to solve for a in that 45xyz... example above, when you can simplify the whole thing to 1.
So that is zero exponents.
Next is negative exponents. They aren't QUITE as simple, but the trick to working with them is. And here it is:
Whenever you see a negative exponent, all you do is make it positive, but put the whole thing on the bottom of a fraction under 1, like so:
a-n = 1 / an
Once it's like that, you can apply any or all of the properties of exponents to it without having to deal with the negative anymore.
Just to put some numbers to it, here is an example for you to see what I mean:
= 1 / (a2b3)4
= 1 / a8b12
Hopefully you can see what I mean with these examples. They are just a few shortcuts that will make working with exponents a lot easier for you. Let me know if you need any more explanation about these topics, but for now I will leave it at that.