As shown in the figure, the set of points consisting of $\triangle ABC$ and its interior is denoted as $D$. For any point $P(x, y)$ in $D$, the maximum value of $z = 2x + 3y$ is
As shown in the figure, the set of points consisting of $\triangle ABC$ and its interior is denoted as $D$. For any point $P(x, y)$ in $D$, the maximum value of $z = 2x + 3y$ is