Question

Show that any number of the form 7^n,nEN can never end qith the digit 0

Answer 1

Hope this helps........

Answer 2

Answer:

If 7ⁿ ends with a 0 then it must be divisible by 10 i.e., its prime factors should have the factors of both 2 and 5 since 2×5=10.

But, 7ⁿ=(7×1)ⁿ

Therefore by the fundamental theorem of arithmetic (there are no prime factors of 7 other than 7 and 1) we can conclude that 7ⁿ can not end with 0.