Tìm x, biết:   a) 0,5 - 0,6x = 0,7

a) \(0,5 - 0,6x = 0,7\)

\(0,6x = 0,5 - 0,7\)

\(0,6x =  - 0,2\)

\(x =  - 0,2:0,6\)

\(x =  - \frac{2}{{10}}:\frac{6}{{10}}\)

\(x =  - \frac{2}{{10}}.\frac{{10}}{6}\)

\(x =  - \frac{1}{3}\)

Vậy \(x =  - \frac{1}{3}\).

b) \(\frac{5}{6} + \left( {5x + \frac{3}{2}} \right):\frac{8}{{15}} = 2\frac{1}{{12}}\)

\(\left( {5x + \frac{3}{2}} \right):\frac{8}{{15}} = \frac{{25}}{{12}} - \frac{5}{6}\)

\(\left( {5x + \frac{3}{2}} \right):\frac{8}{{15}} = \frac{{15}}{{12}}\)

\(5x + \frac{3}{2} = \frac{5}{4}.\frac{8}{{15}}\)

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

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

\(5x = \frac{{ - 5}}{6}\)

  \(x =  - \frac{1}{6}\)

Vậy \(x =  - \frac{1}{6}\).