How to determine the domain and range of a rational function?

The domain is essentially what x can equal, so unless there's a square root (where x has to be positive as anything squared is positive) or division (in division, the denominator can't be 0) you should be good for the most part. For the range, it's what y (the output) can equal, so I'd suggest getting the domain then figuring out what the highest and lowest y points are (as well as if y can't be anything)