Problem

Find for what values of natural n

the expression n3 - 7 is divisible by (n-1).

No Euclidean division!

Answer Submission Is Not Available

Form is valid through May 2018

Solution

Dear friends and visitors of the site,

thank you for your replies to the May Problem.

The first to send a correct solution was Emmanuelle.

Congrats to her!

Here is my solution:

n3 -7=( n3 -1)- 6.

So (n-1) is a factor of 6 and is equal to 1,2,3,6.

Thus n can be equal to 2,3,4,7

 

Thank you again and let's try the June Problem.

Yours,

Serge Hazanov