Tìm x, biết: (a) 1 /2 − 3 x = − 2/ 5

Tìm x, biết:

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

(b) \({\left( {x - \frac{1}{3}} \right)^2} = 4\).