\[\left( 2\frac{1}{4}a^{5}b^{3} \right)^{2} \cdot \left( - 3a^{4}b^{4} \right) =\]
\[= \left( \frac{9}{4}a^{5}b^{3} \right)^{2} \cdot \left( - 3a^{4}b^{4} \right) =\]
\[= \frac{81}{16}a^{10}b^{6} \cdot \left( - 3a^{4}b^{4} \right) = - \frac{243}{16}a^{14}b^{10} =\]
\[= - 15,1875a^{14}b^{10}\]