Tìm x biết : 1) x - 3/5 = 1/2

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

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

\(x = \frac{{11}}{{10}}\)

Vậy \(x = \frac{{11}}{{10}}.\)

2) \(\frac{{ - 3}}{5} \cdot x + 1,5 = \frac{5}{2}\)

\(\frac{{ - 3}}{5}x = \frac{5}{2} - \frac{3}{2}\)

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

\(x = 1:\frac{{ - 3}}{5}\)

\(x = \frac{{ - 5}}{3}\)

Vậy \(x = \frac{{ - 5}}{3}.\)

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

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

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

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

 \(x = \frac{{ - 5}}{6}.\)

Vậy \(x = \frac{{ - 5}}{6}.\)