1. The problem statement, all variables and given/known data Suppose that gcd(a,b)=1 and that a|n and b|n. Prove that ab|n. 2. Relevant equations Since we know that gcd(a,b)=1, we can say that ax+by=1 for some x,y as elements of the integer set. 3. The attempt at a solution My professor said I should multiply the entire equation by n, but I still can't figure it out. Any help would be appreciated. Thanks in advance.