


Elucidean Algorithm. Q 4. For each of the following equations, find a solution z Z or prove that no solution z E Z exists (a) 7x 13 mod 83 mod 624; 11 (b) 25x + 3 (c) 36r 1 mod 87. 12 marks In all...
13. (i) For each of the following equations, find all the natural numbers n that satisfy it (a) φ(n)-4 (b) o(n) 6 (c) ф(n) 8 (d) φ(n) = 10 (ii) Prove or disprove: (a) For every natural number k, there are only finitely many natural num- bers n such that ф(n)-k (b) For every integer n > 2, there are at least two distinction integers that are invertible modulo n (c) For every integers a, b,n with n > 1...