Question

show that the number of the form 7^n,n€N cannot have unit digit zero.​

Answer 1

Answer:

Step-by-step explanation:

If 7n has to end with the digit 0 for any natural number n, then it has to be divisible by 10. ie. its prime factorisation should have the factors of both 2 and 5 [ since 10=2x5 ] But we know that 7=7x1 By the fundamental theorem of arithmetics, we also know that there exist no other factors for 7. Thus we conclude that 7n cannot end with the digit 0 for any natural number n.