Đáp án:
$UCLN\left( {72;108;120} \right) = 12$ ;
$UC\left( {71;108;120} \right) = \left\{ {1;2;3;4;6;12} \right\}$
Giải thích các bước giải:
Ta có :
$\begin{array}{l}
72 = {2^3}{.3^2};\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,108 = {2^2}{.3^3}\,;\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,120 = {2^3}.3.5\\
\Rightarrow UCLN\left( {72;108;120} \right) = {2^2}.3 = 12\\
\Rightarrow UC\left( {71;108;120} \right) = U\left( {12} \right) = \left\{ {1;2;3;4;6;12} \right\}
\end{array}$
