\[y = \frac{k}{x};\ \ \ \ A( - 3;4)\]
\[\frac{k}{- 3} = 4 \Longrightarrow k = - 12\]
\[y = - \frac{12}{x};\ \ \ B\left( 2\sqrt{3}; - 2\sqrt{3} \right)\]
\[- \frac{12}{2\sqrt{3}} = - \frac{6}{\sqrt{3}} = - \frac{6\sqrt{3}}{3} = - 2\sqrt{3}\]
\[Ответ:k = - 12;\ \ \ \]
\[да,\ принадлежит.\]