It means "not equal".

ragequitter, you should take a gander at

Online LaTeX Equation Editor
and add a little Latex markup to your posts.

is achieved by "\neq" between tex tags.

There is a general way for determining the domain of real-valued functions such as the ones you listed.

1. Start with all real numbers.

2. Exclude any values that would lead to zero in the denominator, or a negative under an even radical (including square roots, 4th roots, etc). logarithms must have positive arguments also, but we're looking at rational functions (adjoin sqrt) for the moment.

The bottom cannot be zero, so solve

to get

That. Is. It! Sure, you can write that in interval notation, but the result is the same.

--------------------

For the range, it's not as cut-and-dry. You can't always solve for x. More advanced techniques might come into play.

It's a shame that you aren't familiar (comfortable) with end behavior (i.e. "limits at infinity") and the like.

Have you heard about even/odd functions? You can use symmetry in the case of y as given above.

You can use partial fraction decomposition... actually, that might be best in this case. I suspect the range is (almost?) every real number.