Đáp án đúng: A
Giải chi tiết:\(\begin{array}{l}\,\,\frac{2}{3}x - \frac{3}{2}\left( {x - \frac{1}{2}} \right)\,\,\,\,\,\,\, = \frac{5}{{12}}\\\,\,\,\,\,\,\frac{2}{3}x - \left( {\frac{3}{2}x - \frac{3}{2} \cdot \frac{1}{2}} \right) = \frac{5}{{12}}\\\,\,\,\,\,\,\frac{2}{3}x - \frac{3}{2}x + \frac{3}{4}\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{5}{{12}}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\frac{{ - 5}}{6}x + \frac{3}{4}\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{5}{{12}}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\frac{{ - 5}}{6}x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{5}{{12}} - \frac{3}{4}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\frac{{ - 5}}{6}x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{{ - 1}}{3}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{{ - 1}}{3}:\frac{{ - 5}}{6}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \,\,\,\,\,\,\,\frac{2}{5}\end{array}\)
Chọn A
