\[\frac{\left( - 2a^{3}b^{2} \right)^{2} \cdot \left( - a^{2}b^{3} \right)^{3}}{4\left( \left( \text{ab} \right)^{4} \right)^{3}} =\]
\[= \frac{4a^{6}b^{4} \cdot \left( - a^{6}b^{9} \right)}{4a^{12}b^{12}} =\]
\[= \frac{- 4a^{12}b^{13}}{4a^{12}b^{12}} = - b;\]
\[b = - 2,7:\]
\[- b = 2,7.\]
\[Ответ:2,7.\]