mastiff/ boxer temper

Question
My dog has bitten me on several different occasions out of anger and I care for it very well. He is only three months, but when he get's angry he will growl at me and when I attempt to grab by the collar, he becomes viscious and bites me. Has bitten 2 neighbors as well. Should I get rid of him or try to work with him?

Answer
Hi
First I need some answers,,,,what is happening when he is biting?  Where did you get him from and how long have you had him?  I see that he is part mastiff.  That can be a vert aggressive dog.  I will probably suggest you get a different dog as mastiffs can tend to take advantage.
nancy