Решение:
\(\sqrt{\frac{25}{2}-12}\)
\(12 = \frac{12 \cdot 2}{2} = \frac{24}{2}\)
\(\sqrt{\frac{25}{2}-\frac{24}{2}} = \sqrt{\frac{1}{2}}\)
\(\sqrt{\frac{1}{2}} = \frac{\sqrt{1}}{\sqrt{2}} = \frac{1}{\sqrt{2}}\)
\(\frac{1}{\sqrt{2}} = \frac{1 \cdot \sqrt{2}}{\sqrt{2} \cdot \sqrt{2}} = \frac{\sqrt{2}}{2}\)
Ответ: \(\frac{\sqrt{2}}{2}\).