Question

prove if aub = anb then a=b

Answer 1

I'm assuming U and N are union and intersection symbols?

Answer 2

If everything in both a and b (the union) is in the intersection, then.
a = the union of a and b
b = the union of a and b
a = b

I feel like something's missing from the beginning of that, but I'm not sure what.

Answer 3

Thanks, I got it out :) just realised what I needed to do