Решите систему неравенств -0,3x<=1,6; -0,4x>2,1; 0,72x<=-3,84.

\[\left\{ \begin{matrix}
- 0,3x \leq 1,6\ \ \ \ \ \\
- 0,4x > 2,1\ \ \ \ \\
0,72x \leq - 3,84 \\
\end{matrix} \right.\ \Longrightarrow \left\{ \begin{matrix}
x \geq - \frac{16}{3}\text{\ \ \ } \\
x < - \frac{21}{4}\text{\ \ } \\
x \leq - \frac{384}{72} \\
\end{matrix} \right.\ \]

\[\left\{ \begin{matrix}
x \geq - 5\frac{1}{3} \\
x < - 5,5 \\
x \leq - 5\frac{1}{3} \\
\end{matrix} \right.\ \Longrightarrow x = - 5\frac{1}{3}.\]

\[Ответ:\ - 5\frac{1}{3}.\]