Relax

Respuesta :

Assuming the sequence goes on like this 11,-33,99,-297,891,...,
its general formula is [tex]a_n=-11\cdot(-1)^n\cdot3^{n-1}[/tex]

So, the 9th term is
[tex]a_9=-11\cdot(-1)^9\cdot3^{9-1}=-11\cdot(-1)\cdot6561=72171[/tex]