I'm hoping this is the right category, since it's set theory. If it's not I'll move it if someone knows a better place for these questions
Prove that A X (B_{1}U B_{2}) = (A X B_{1}) U (A X B_{2})
I am actually stuck on the B_{1} B_{2} in this problem. It's some notation aspect that is keeping me from understanding what the problem is asking for. Are B_{1} and B_{2} separate sets?