Question

Answer 1

b: UCLN(42;56;72)=2

Answer 2

a,BCNN: 1200 suy ra bội chung có dạng 1200k

b,UCLN :2 .ước chung là 1, 2

Answer 3

\(a.120=2^3.3.5\)          \(240=2^4.3.5\)        \(300=2^2.3.5^2\)

\(BCNN\left(120;240;300\right)=2^4.3.5^2=1200\)

\(BC\left(120;240;300\right)=\left\{0;1200;2400;3600;...\right\}\)

 \(b.42=2.3.7\)          \(56=2^3.7\)        \(72=2^3.3^2\)

\(ƯCLN\left(42;56;72\right)=2\)

\(ƯC\left(42;56;72\right)=\left\{1;2\right\}\)