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# Find the LCM and HCF of the following integers by applying the prime factorisation method. 1.12, 15 and 212.17, 23 and 293.8, 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 = $$2^3 × 3^2 × 5^2 = 1800$$