Question

aratati ca 5 la n+2+5 la n +1- 5 la n divizibil cu 145 dau coroana!!!

Answer 1

$5^{n+2}+ 5^{n+1}-5^n=5^n*5^2+5^n*5-5^n=5^n(5^2+5-1)=$
$5^n(25+5-1)=5^n*29= 5^{n-1}*5*29= 5^{n-1}*145$