d. \( \frac{6}{7} \cdot\left(-\frac{2}{5}\right)-\frac{8}{9}:(-1,25)= \)

To tackle this expression, first, let's simplify the multiplication and the division step by step. The first part is \( \frac{6}{7} \cdot \left(-\frac{2}{5}\right) \). When multiplying a positive fraction by a negative fraction, the result will be negative. So, we calculate: \[ \frac{6 \cdot (-2)}{7 \cdot 5} = \frac{-12}{35} \] Next, let's deal with the division part: \( \frac{8}{9} : (-1.25) \). First, convert \(-1.25\) to a fraction: \(-1.25 = -\frac{5}{4}\). Dividing by a fraction is the same as multiplying by its reciprocal, so we have: \[ \frac{8}{9} \cdot \left(-\frac{4}{5}\right) = \frac{8 \cdot (-4)}{9 \cdot 5} = \frac{-32}{45} \] Now, we combine both parts. We have: \[ \frac{-12}{35} - \frac{-32}{45} \] This can be rephrased as adding the two fractions: \[ \frac{-12}{35} + \frac{32}{45} \] To perform this addition, we must find a common denominator. The least common multiple (LCM) of 35 and 45 is 315. Now, we convert both fractions: \[ \frac{-12}{35} = \frac{-12 \cdot 9}{35 \cdot 9} = \frac{-108}{315} \] \[ \frac{32}{45} = \frac{32 \cdot 7}{45 \cdot 7} = \frac{224}{315} \] Now we can add: \[ \frac{-108}{315} + \frac{224}{315} = \frac{116}{315} \] Therefore, the final result is: \[ \boxed{\frac{116}{315}} \]