Question

daca 4la n+4 la n+1=10*2 la 2005 atunci n=...

Answer 1

$4^n+4^{n+1}=10*2^{2005}$
$4^n(4+1)=5*2*2^{2005}$ - Impartim cu 5 
$4^n = 2^{2006}$
2n = 2006 => n = 1003