\[\sqrt{(8 - x)(7 - 3x)}\]
\[(8 - x)(7 - 3x) \geq 0\]
\[(x - 8)(3x - 7) \geq 0\]
\[3\left( x - \frac{7}{3} \right)(x - 8) \geq 0\]
\[x \leq \frac{7}{3};\ \ x \geq 8.\]
\[Ответ:x \leq 2\frac{1}{3};\ \ x \geq 8.\]