a)-812; 6)-63: (-21); в) 0,8 (-2,6); г) -7 \(\frac{6}{7}\): \(\left(-9\frac{3}{7}\right)\)

Решаем по действиям:

1. a) \(-8 \cdot 12 = -96\)

2. б) \(-63 : (-21) = 3\)

3. в) \(0.8 \cdot (-2.6) = -2.08\)

4. г) \(-7 \cdot \frac{6}{7} : \left(-9\frac{3}{7}\right) = -7 \cdot \frac{6}{7} : \left(-\frac{66}{7}\right) = -6 : \left(-\frac{66}{7}\right) = -6 \cdot \left(-\frac{7}{66}\right) = \frac{42}{66} = \frac{7}{11} \approx 0.64\)