Đáp án:
Giải thích các bước giải:
\(\begin{array}{l}a,\left( {30;150} \right)\\30 = 2.3.5\\150 = {2.3.5^2}\\ \Rightarrow BCNN\left( {30;150} \right) = {5^2}.2.3 = 150\end{array}\)
\(\begin{array}{l}b,\left( {40;28;140} \right)\\40 = {2^3}.5\\28 = {2^2}.7\\140 = {2^2}.5.7\\ \Rightarrow BCNN\left( {40;28;140} \right) = {2^3}.5.7 = 280\end{array}\)
\(\begin{array}{l}c,\left( {100;120;200} \right)\\100 = {2^2}{.5^2}\\120 = {2^3}.3.5\\200 = 2.2.5.2.5 = {2^3}{.5^2}\\ \Rightarrow BCNN\left( {100;120;200} \right) = {2^3}{.5^2}.3 = 600\end{array}\)
