Question

For every natural number $n,3^{2n+2}-8n-9$ is divisible by

Answer 1

Answer: 16

$3^{2n+1}-8n-9,\forall n\in N$
Putting $n=2$
$\Rightarrow 3^{2\times 2+2}-8\times 2-9$
$=729-16-9$
$=704$
It is divisible by $16$