Answer
Error: the common ratio is incorrect.
The common ratio: $6$ and not $-6$.
The correct equation for the $n$th term is $a_{n}=-2(6)^{n-1}$.
Work Step by Step
The common ratio shown is incorrect.
Common ratio $r=\frac{-12}{-2}=6$.
The common ratio is $6$ and not $-6$.
The correct equation for the $n$th term is therefore
$a_{n}=-2(6)^{n-1}$.
