試題詳解

11. (3%) Let x= a+ bk be the solution of the system of congrucnces x = 7 (mod 9), x≡ 4 (mod 12),and x≡16 (mod 21), where a and b are the smallest positive integer, k e Z. Which is the correct value of (2a+b) mod 11?
(A)9
(B) 7
(C) 4
(D) 6