Im new and working on a proof - well actually i cant even start this proof.

If gcf (n,a) >1 prove there exists b not equal unto 0 mod n but a*b = 0 mod n.

Im even told that b = n/gcf(n,a)

any ideas or help will surely be appreciated and allow me to actually spend time with my family instead of staring at this problem for 4 hours getting nowhere.....

windoze