What should I do with the tenant rental Check?

[Michael C.]

I just bought a duplex, I'm living in one side and renting out the other, my question is should I put the tenant rental check in a bank account and use my job money to pay the mortgage or directly send the check to my mortgage and pay the difference? If I did the bankaccount option wouldnt it be tax as income? And i also have a roomate whos paying me too, should I put that in a seperate account? And am I require to write a lease for my roomate? Thanks!