I'm really having trouble with this proof. at first I thought, oh easy the a's cancel then I realized I am proving that property so that was no help at all. Here is my work so far: --snip-- Let a, b, and c be integers with a≠0. If ab|ac, we know from the definition of "divides" that there is an integer k, such that ac=ab⋅k Then (a - c⋅k) = 0 so k(a - b⋅k) = 0 Since we know that a≠0, then b|c. --snip-- I'm pretty sure that I'm off the rails after "such that ac=ab⋅k" any one care to help me? please?