Prove by Mathematical Induction
Hi everyone I need a little help, Im stuck.
I have to prove by induction that:
is exactly divisible by 7 for all positive integers of n.
Now what I have done is:
If is divisible by 7
=>( )-----> Pn statement
where a is a positive integer
2) statement where n=1
Therefore is true.
3) Assuming to be true where n=k
Now here is where Im stuck, Im not getting to factor out a 7 i.e.
getting 7(some integer) to prove that is divisible by 7.
Any help would be greately appreciated.