Question

(a) If a is a unit in Z_n, prove a is not a zero divisor.
(b) If a is a zero divisor in Z_n, prove a is not a unit(i.e. Contrapositive)

Answer 1

\(\text {let } ~a ~\text{be unit in} ~ z_n\\ \text{which mean } \forall b<n \in z_n
ab=1 mod n\\ \)
lol
will work ltr on this :3