Tìm x, biết: 1/3x + 2/5(x-1) = 0

\[\frac{1}{3}x + \frac{2}{5}\left( {x - 1} \right) = 0\]

\[\frac{1}{3}x + \frac{2}{5}x - \frac{2}{5} = 0\]

\[\frac{1}{3}x + \frac{2}{5}x = \frac{2}{5}\]

\[x\left( {\frac{1}{3} + \frac{2}{5}} \right) = \frac{2}{5}\]

\[x \cdot \frac{{11}}{{15}} = \frac{2}{5}\]

\[x = \frac{2}{5}:\frac{{11}}{{15}}\]

\[x = \frac{6}{{11}}\]

Vậy \[x = \frac{6}{{11}}.\]