\(\Leftrightarrow\left\{{}\begin{matrix}4n+4+3n-6< 19\\n^2-6n+9-n^2+16< =43\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}7n-2< =19\\-6n+25< =43\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}n< =3\\n>=-3\end{matrix}\right.\Leftrightarrow-3< =n< =3\)