\[f(x) = (x - 2) \cdot \sqrt{x - 3},\ \ \]
\[x - 3 \geq 0,\ \ x \geq 3\]
\[(x - 2) \cdot \sqrt{x - 3} = 0\]
\[x = 2,\ \ x = 3\]
\[Ответ:3.\]