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


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