\[2\frac{8}{9} < \frac{x}{9} < 3\frac{7}{9};\ \ где\ \]
\[x - натуральное\ число.\]
\[\frac{26}{9} < \frac{x}{9} < \frac{34}{9}\]
\[26 < x < 34.\ \ \]
\[x = \left\{ 27;\ 28;29;30;31;32;33 \right\}.\]