Question

find the LCM and HCF OF 12,15 AND 21

Answer 1

Prime factorization of 12 = 2 * 2 * 3

Prime factorization of 15 = 3 * 5

Prime factorization of 21 = 3 * 7


HCF(12,15,21) = 3.


LCM(12,15,21) = 2 * 2 * 3 * 5 * 7

                       = 420.



Hope this helps!

Answer 2

Answer:

$\bold{\blue{ \underline{ \underline{prime \: factorisation : - }}}}$

$\huge \boxed{lcm \: of \: 12.15.21}$

$\bold{ \sf{12 = 1.2.3.4.6.12}}$

$\bold {\sf{15 = 1.3.5.15}}$

$\bold{ \sf{21 = 1.3.7}}$

$\sf{lowest \: common \: factor \: of \: 12.15.21 \: is \: (3)}$

$\bold \red{ - - - - - - - - - - - - - - }$

$\huge \boxed{hcf}$

$\sf{ 12 = 1 \times 2 \times 2 \times 3}$

$\sf{15 = 1 \times 3 \times 5}$

$\sf{21 = 1 \times 3 \times 7}$

$\sf{ = > 2 \times 2 \times 3 \times 5 \times 7}$

$= > 420$