(1/5)√(1 9/16) − (2/3)√(1 17/64)

Преобразуем смешанные числа: \(1\frac{9}{16}=\frac{25}{16}\), \(1\frac{17}{64}=\frac{81}{64}\).

\(\frac{1}{5}\sqrt{\frac{25}{16}}-\frac{2}{3}\sqrt{\frac{81}{64}}=\frac{1}{5}\cdot\frac{5}{4}-\frac{2}{3}\cdot\frac{9}{8}=\frac{1}{4}-\frac{3}{4}=-\frac{1}{2}\).

Ответ: −1/2.