Mathematics for IGCSE & O level - Number (Section 2 - No. 15)
If a = 2^2 x 3 x 5 and b = 2 x 3^2 x 7, what is the HCF of a and b?
6
12
30
420
Explicação
To find the HCF, take the lowest power of each common prime factor. Both a and b share the factors 2 and 3. The lowest power of 2 is 2^1 and of 3 is 3^1. Therefore, HCF = 2 x 3 = 6.