1. compute the least non-negative residue of 4^n (mod 9) for
n=1,2,3,4,5.... prove that 6*(4^n)=6 (mod 9) for every n>0.
2. find nice tests for divisibility of numbers in base 34 by
each of 2,3,5,7,11,and 17.
3. in Z/15Z, find all solutions of : (i) [36]X=[78]. (ii)
[42]X=[57] (iii) [25]X=[36]
4. in Z/26Z, find the inverse of [9], [11], [17], and [22]
4. write the set of solutions of x=5 mod24. x=17 (mod 18)
for all equation line, there are...