#### Answer

$a_{5}=a_{1}\times r^{4}=-\dfrac {4}{3}\times 3^{4}=-108;$
$a_{n}=a_{1}\times \left( r\right) ^{n-1}=-\dfrac {4}{3}\times 3^{n-1}$

#### Work Step by Step

$a_{2}-u_{1}\times r\Rightarrow -4=a_{1}\times 3\Rightarrow a_{1}=-\dfrac {4}{3};a_{5}=a_{1}\times r^{4}=-\dfrac {4}{3}\times 3^{4}=-108;a_{n}=a_{1}\times \left( r\right) ^{n-1}=-\dfrac {4}{3}\times 3^{n-1}$