Có: 6 = 2 . 3
4 = 22
=> BCNN (6, 4) = 22 . 3 = 12
=> BC (6,4) = B (12) = {0 ; 12 ; 24 ; 36 ; 48 ; 60 ; ...}
Vì 16 ≤ x ≤50 => x ∈ {24 ; 36 ; 48}
Bài làm
Ta có: 4=22
6=2.3
=>BCNN(6,4)=22.3=12
=>BC(6,4)=B(12) mà x\(\in\)BC(6,4)
=> x\(\in\)B(12)={1;2;3;4;6;12}
Vậy x\(\in\){1;2;3;4;6;12}