I would like to know how a person gets taxed for income from a job and separate income from a LLC that I operate as my own business in the US. For example, if I generate 100k from my job; and if I generate 20k from the LLC and after expenses, if I make 10k from it as profit, do I get taxed for 100k+10k or 100k separately and 10k separately?

If I get taxed separately, then is there a minimum income threshold, for the income from the LLC, until which I don't get taxed?