\(\left\{{}\begin{matrix}x+y=19\\xy+6x=150\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=19-y\\x\left(y+6\right)=150\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=19-y\\\left(19-y\right)\left(y+6\right)=150\end{matrix}\right.\Leftrightarrow}\left\{{}\begin{matrix}x=19-9=10\\y=9\end{matrix}\right.\)