Tu hai ragione is an Italian equivalent of 'You are right'. The subject pronoun 'tu' means 'you'. It doesn't have to be used, because the verb identifies the subject as the second person singular....
i just usually just say "e tu" which means "and you" or basically "you too." of course I'm not the best in Italian, but i have a few friends/family who are Italian, and it always seems to work whe...