Question

1. if a divides b and a divides c
then a divides gcd(b,c). help so far I have this
proof: assume a/b and a/c so a=bp and a=cq for some p and q an element of an integer........

Answer 1

mainly you wanna prove that any common divisor d of b and c is less than or equal gcd(b,c) and also d|gcd(b,c)

Answer 2

which is already in gcd definition see this post.

http://openstudy.com/study#/updates/55eac022e4b0819646d98287