\[5x^{2}y^{3} = - 7\]
\[x^{2}y^{3} = - \frac{7}{5}\]
\[\left( x^{2}y^{3} \right)^{2} = \left( - \frac{7}{5} \right)^{2}\]
\[x^{4}y^{6} = \frac{49}{25}\]
\[5x^{4}y^{6} = 5 \cdot \frac{49}{25} = \frac{49}{5} = \frac{98}{10} = 9,8.\]
\[Ответ:9,8.\]