\[4\sqrt{\frac{15}{8}}\ \ и\ \ \ \frac{1}{5}\sqrt{750}\]
\[4\sqrt{\frac{15}{8}} = \sqrt{\frac{16 \cdot 15}{8}} = \sqrt{30};\ \ \ \ \]
\[\frac{1}{5}\sqrt{750} = \sqrt{\frac{7 \cdot 50}{25}} = \sqrt{30};\ \ \ \]
\[\sqrt{30} = \sqrt{30}\]
\[4\sqrt{\frac{15}{8}} = \frac{1}{5}\sqrt{750}.\]