Question

show that 7 n cannot end with the digit zero , for any natural number n.

Answer 1

We know 8n = (23)n = 23n

If 8n end with zero then 10 is factor of 8n.

8n = 23n =(5)(2)

5 is factor of 2, which is a contradiction

So, our assumption is wrong. Hence 8n cannot end with zero