\( a) (-3)^2 + 2^3 \cdot 6 : 3 - \frac{5}{7} \cdot \frac{3}{12} = 9 + 8 \cdot 2 - \frac{5}{7} \cdot \frac{1}{4} = 9 + 16 - \frac{5}{28} = 25 - \frac{5}{28} = \frac{25 \cdot 28 - 5}{28} = \frac{700 - 5}{28} = \frac{695}{28} \)
Ответ: \(\frac{695}{28}\)