Tìm x, biết: 11/15-(7/9 x).3/8=61/90 x/3

Lời giải:

\[\frac{{11}}{{15}} - \left( {\frac{7}{9} + x} \right) \cdot \frac{3}{8} = \frac{{61}}{{90}} + \frac{x}{3}\]

\[\frac{{11}}{{15}} - \frac{7}{{24}} - \frac{{3x}}{8} - \frac{{61}}{{90}} - \frac{x}{3} = 0\]

\[\frac{{ - 17}}{{72}} - \left( {\frac{{3x}}{8} + \frac{x}{3}} \right) = 0\]

\[\frac{{17}}{{24}}x =  - \frac{{17}}{{72}}\]

\[x =  - \frac{1}{3}\]

Vậy \[x =  - \frac{1}{3}\]