Hi, I'm taking notes to help me with my functions homework tonight and I'm not clear about the part about "domains". I was hoping someone here could clarify what it means.

Example: Let f(x) = 1/x-2 and g(x)= square root of x. Solve f+g (x) and find the domain.

What exactly does "domain" mean and how exactly do I find it?

Please assume that I am a math dummy and explain clearly and step by step if you can. Thank you in advance.