Find the LCM and HCF of the following integers by applying the prime factorisation method.

(i) 12, 15 and 21

(ii) 17, 23 and 29

(iii) 8, 9 and 25

(i) 12 = 2×2×3 = 2²×3

15 = 3×5

21 = 3×7

HCF = 3

LCM = 2²×3×5×7 = 420

(ii) 17 = 1×17

23 = 1×23

29 = 1×29

HCF = 1

LCM = 17×23×29 = 11339

(iii) 8=2×2×2

9 = 3×3

25 = 5×5

HCF = 1

LCM = 2×2×2×3×3×5×5 = 1800