Find the LCM and HCF of the following integers by applying the prime factorisation method.
1.12, 15 and 21
2.17, 23 and 29
3.8, 9 and 25

1.12, 15 and 21
\(12 = 2^2 × 3\)
\(15 = 3 × 5\)
\(21 = 3 × 7\)
HCF = 3
LCM = \(2^2 × 3 × 5 × 7 = 420\)


2.17, 23 and 29
\(17 = 1 × 17\)
\(23 = 1 × 23\)
\(29 = 1 × 29\)
HCF = 1
LCM = \(17 × 23 × 29 = 11339\)


3.8, 9 and 25
\(8 = 2 × 2 × 2 = 2^3\)
\(9 = 3 × 3 = 3^2\)
\(25 = 5 × 5 = 5^2\)
HCF = 1
LCM = \(2^3 × 3^2 × 5^2 = 1800\)