Why do we need these rules? Let's go back to an old example from rule #2:
Look at this carefully... It makes sense, doesn't it? The problem was that the -2 exponent was confusing... So, we need a way to deal with it.
Check out an example with just numbers:
One of the games we'll be playing is to rewrite things so that there are no negative exponents.
Check it out:
This negative is not effected!