I dont quite know how to attack this.
Here is the problem.
(a divides b) or (a divides c) implies a divides bc.
any help at all would be greatly appreciated
I am going to assume that a divides only b. (We can simply switch the roles of b and c if a divides c and not b, so we are losing no generality here by doing this.)
So a|b implies that b = na, where n is some positive integer. Thus
bc = (na)c = (nc)a
But nc is also a positive integer. Thus a|bc as well.