Сначала упростим правую часть уравнения.
\( \frac{8}{14} = \frac{8 \cdot 3}{14 \cdot 3} = \frac{24}{42} \)
\( \frac{6}{21} = \frac{6 \cdot 2}{21 \cdot 2} = \frac{12}{42} \)
\( \frac{24}{42} - \frac{12}{42} = \frac{12}{42} = \frac{2}{7} \)
\( \delta - 0.59 = \frac{2}{7} \)
\( \frac{2}{7} \approx 0.2857 \)
\( \delta - 0.59 = 0.2857 \)
\( \delta = 0.59 + 0.2857 = 0.8757 \)
Ответ: \( \delta \approx 0.8757 \).