\[\frac{- 3 \cdot \left( a^{7} \right)^{4} \cdot \left( b^{13} \right)^{3}}{2 \cdot \left( a^{9} \right)^{3} \cdot \left( b^{8} \right)^{5}} =\]
\[= \frac{- 3a^{28} \cdot b^{39}}{2a^{27} \cdot b^{40}} = \frac{- 3a}{2b}\]
\[a = 1,8;\ \ b = 0,27:\text{\ \ }\]
\[\ \frac{- 3 \cdot 1,8}{2 \cdot 0,27} = \frac{- 5,4}{0,54} = - 10.\]