\[y = kx²;\ \ \ \ D(3; - 36)\]
\[k \cdot 9 = - 36 \Longrightarrow k = - 4\]
\[y = - 4x^{2};\ \ \ K\left( - 2\sqrt{3};48 \right)\]
\[- 4 \cdot \left( - 2\sqrt{3} \right)^{2} = - 4 \cdot 4 \cdot 3 =\]
\[= - 48 \neq 48\]
\[Ответ:k = - 4;\ \ \ \]
\[нет,\ не\ принадлежит.\]