Question

explain why 42n can not end with zero also find unit place digit in the expansion of 42n if n =17

Answer 1

if the no. 42n were end with 0 it would be divisible by 5 that is prime factorisation of 42n contain 5 but prime factorisation of 42n does not contain 5.so,the uniqueness of fundamental theorem does not show other factorisation of 42. Therefore 42n does not end with 0