# Math Help - Proof Method and strategy

1. ## Proof Method and strategy

Hi,

I am not able to solve this by proper method. Please someone help.

Show that if n is perfect square then n-1 is not prime number for all interger n>4.

2. Originally Posted by micky_577
Show that if n is perfect square then n-1 is not prime number for all interger n>4.
Do you know this web-page?

3. Buddy,

I did not understand that. Is'nt prefect number is different than perfect squre? Please help me solve the question.

Thanks

4. I would argue that if n is a perfect square i.e $n=a^2$ then $n-1 = a^2-1$ , now $a^2-1$ can be factored into $(a-1)(a+1)$ and in turn so can n-1 so it cannot be prime.

5. Originally Posted by micky_577
Buddy,
I did not understand that. Is'nt prefect number is different than perfect squre? Please help me solve the question.
First of all, I doubt that I am your ‘buddy’. I have no idea who you could be.
From this reply it is clear that you don’t even understand your own question.

6. Please accept my sincere apology Plato. You are really correct in saying that I really did not understand question but I am trying learn man.

Thank you very much for your help.