Question

Prove that 4^n-3n-1 is a multiple of 9 for every n belongs N​

Answer 1

Yes, It is true. 4^n-3n-1 is a multiple of 9

If we put n=1,then
4^1-3(1)-1=0
and 0 is a multiple of 9

If we put n=2,then
4^2-3(2)-1=9
and 9 is a multiple of 9

Hence proved.

Answer 2

Hello!
I will be proving this by Principle of Mathematical Induction which is the proper way to do in these questions to get marks in schools.Here is my working..
Regards.