Hello!
With some functions, there are a few ways to find the domain and range without a graph. One key way to find numbers that are not part of the domain is to look for undetermined numbers, such as x/0. Numbers like these are undetermined. You could also look for numbers that the function could accept, such as having a certain input be equal to a certain output or range, which isn't as common but can still be helpful in some situations.
I hope this helps!