Solve the congruence b) 5x 6 mod 7 c) 5x 0 mod 7 Solution We have 5x 6 mod 7 and 5x 0 mod 7. As per the 1st congruence, 5x = 6+7p, where p is an integer and as per the 2nd congruence, 5x = 7q, where q is an integer. These two equations are apparently inconsistent as 6 is not a multiple of 7. Therefore, the given congruences are inconsistent. There is no solution..