\[z - \frac{4}{9}z = 4,5\]
\[\frac{5}{9}z = 4,5\]
\[z = 4,5\ :\frac{5}{9} = 4,5 \cdot \frac{9}{5}\]
\[z = 0,9 \cdot 9 = 8,1.\]
\[Ответ:z = 8,1.\]