Question

Answer 1

a: {1;2;3;5;6;10;15;30}

b: {0;6;12;18;24;30;36;42;48}

c: C={18;36;72}

Answer 2

a, Ư(30) = { 1; 2; 3; 5; 6; 10; 15; 30 }

b, B(6) = { 6; 12; 18; 24; 30; 36; 42; 48 }

c, B(18) = {0; 18; 36; 54; 72; …}

  Ư(72) = {1; 2; 3; 4; 6; 8; 9; 12; 18; 24; 36; 72}

=> x {18; 36; 72}