5.89 Найдите корень уравнения: в) \(\frac{1}{5}(5x - 10) - \frac{2}{9}(9x - 27) = 9\); г) 4,2(3z - 5) - 1,4(5z - 3) = 5,6.

\[\frac{1}{5} \cdot 5x - \frac{1}{5} \cdot 10 - \frac{2}{9} \cdot 9x + \frac{2}{9} \cdot 27 = 9\]

\[x - 2 - 2x + 6 = 9\]

\[-x + 4 = 9\]

\[-x = 9 - 4\]

\[-x = 5\]

\[x = -5\]

\[4.2 \cdot 3z - 4.2 \cdot 5 - 1.4 \cdot 5z + 1.4 \cdot 3 = 5.6\]

\[12.6z - 21 - 7z + 4.2 = 5.6\]

\[5.6z - 16.8 = 5.6\]

\[5.6z = 5.6 + 16.8\]

\[5.6z = 22.4\]

\[z = \frac{22.4}{5.6}\]

\[z = 4\]