$$5\sqrt{\frac{7}{5}} \text{ и } \frac{1}{2}\sqrt{140}$$
$$(5\sqrt{\frac{7}{5}})^2 = 25 \cdot \frac{7}{5} = 5 \cdot 7 = 35$$
$$(\frac{1}{2}\sqrt{140})^2 = \frac{1}{4} \cdot 140 = 35$$
$$35 = 35$$
$$5\sqrt{\frac{7}{5}} = \frac{1}{2}\sqrt{140}$$
Ответ: $$5\sqrt{\frac{7}{5}} = \frac{1}{2}\sqrt{140}$$