$$\left. \begin{array} { l } { n a \lt 0 ] } \\ { 6 \text { a n d t h e i r \right.$$
$o=6$
$\left\{\begin{matrix}n<0\text{, }&a>0\text{ and }o=6\\n>0\text{, }&a<0\text{ and }o=6\end{matrix}\right.$
