Help! My dog keeps biting my roommate?

I have a 2 year old male beagle Pitt mix who never showed any signs of aggression prior to this. My roommate and my dog have always loved eachother so I’m so confused. About 6 months ago my roommate got a male Pitt which is advised against because neither of the dogs are neutered. They play rough and occasionally... show more I have a 2 year old male beagle Pitt mix who never showed any signs of aggression prior to this. My roommate and my dog have always loved eachother so I’m so confused. About 6 months ago my roommate got a male Pitt which is advised against because neither of the dogs are neutered. They play rough and occasionally mg dog will snap at him but nothing serious. A few weeks ago we had people over and it was quite noisy and my dog was hiding under the coffee table and my roommate disciplined her dog near the table and my dog snapped and bit her leg. And then today she was trying to get him out of a room and he bit her! I am going to make an appointment to get him neutered in hopes that will stop the aggression? Does anyone have advice? I can’t afford a professional to train him and he really is a great dog.
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