Tìm x, biết: a) x + − 2/3 = 1/3 ; b) | 2x − 1 | + 2 = 5 .

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

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

     \(x = \frac{3}{3} = 1\)

Vậy \(x = 1\).

b) \(\left| {2x - 1} \right| + 2 = 5\)

     \(\left| {2x - 1} \right| = 3\)

Trường hợp 1:

\(2x - 1 = 3\)

\(2x = 4\)

\(x = 2\)

Vậy \(x \in \left\{ {2; - 1} \right\}\).

Trường hợp 2:

\(2x - 1 = - 3\)

\(2x = - 2\)

\(x = - 1\)