Write a python program that solves the congruence ax b (mod m).

[If gcd(a,m) does not divide c, return an error message and the value of gcd(a,m).]

Test your program by finding all of the solutions to the congruences:

72x 47 (mod 200)

4183x 5781 (mod 15087)

1537x 2863 (mod 6731)