Thinking Mathematically (6th Edition)

$a_{12}=-30$
Recall: The $n^{th}$ term ($a_n$) of an arithmetic sequence is given b the formula: $a_n=a_1+(n-1)d$ where $d$=common difference $a_1$=first term. Thus, for the given arithmetic sequence, \begin{align*} a_{12}&=a_1+(12-1)d\\ a_{12}&=-8+(11)(-2)\\ a_{12}&=-8-22\\ a_6&=-30 \end{align*}