I am using == to denote congruency:
a== b (modm) meaning a is congruent to b (modm)
(or m divides a-b)
Suppose A is the set of integers
Let a,b,m be elements of A such that m>=2.
Prove "If a == b(modm) then gcd(a,m)=gcd(b,m)"
Everytime I try to do this, I get stuck.
Thank you for your help.