Question

Prove this: If a|30, then a|60

Answer 1

If a | 30, then ak = 30 for some integer k


Now multiply both sides by 2 to get 2ak = 60 and rearrange terms to get a(2k) = 60


So because a(2k) = 60, this means that a | 60


So we've shown that if a | 30, then a | 60

Answer 2

ok man this makes perfect sense now thanks alot