I'm having some trouble addressing the following two questions in a text I am going through:
1. Show that n is a prime number iff whenever a,b ∈ Zn with ab=0, we must have that a=0 or b=0.
2. Show that n is a prime number iff for every a,b,c ∈ Zn satisfying a not =0, and ab=ac, we have...