Tìm x biết a) x + (-1/9) = -7/6

a) \(x + \left( { - \frac{1}{9}} \right) = \frac{{ - 7}}{6}\)

\(x = \frac{{ - 7}}{6} - \left( {\frac{{ - 1}}{9}} \right)\)

\(x = - \frac{7}{6} + \frac{1}{9} = \frac{{ - 19}}{{18}}\)

Vậy \(x = \frac{{ - 19}}{{18}}.\)

b) \(\left( {x - \frac{4}{7}} \right):\frac{{ - 5}}{3} = 0,2\)

\(x - \frac{4}{7} = 0,2 \cdot \frac{{ - 5}}{3}\)

\(x - \frac{4}{7} = \frac{1}{5} \cdot \frac{{ - 5}}{3}\)

\(x - \frac{4}{7} = - \frac{1}{3}\)

Vậy \(x = \frac{5}{{21}}.\)

c) \({\left( {2x - \frac{1}{3}} \right)^3} = \frac{1}{8}\)

\({\left( {2x - \frac{1}{3}} \right)^3} = {\left( {\frac{1}{2}} \right)^3}\)

\(2x - \frac{1}{3} = \frac{1}{2}\)

\(2x = \frac{1}{2} + \frac{1}{3} = \frac{5}{6}\)

\(x = \frac{5}{{12}}\)

Vậy \(x = \frac{5}{{12}}.\)