Đáp án đúng: A
Giải chi tiết:\(\begin{array}{l}\,\,2\frac{2}{5}:\left( {\frac{1}{2}x - 0,75} \right) = \frac{3}{{10}}\,\,\\ \Leftrightarrow \frac{{12}}{5}:\left( {\frac{1}{2}x - \frac{3}{4}} \right) = \frac{3}{{10}}\,\,\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\frac{1}{2}x - \frac{3}{4}\,\,\,\, = \frac{{12}}{5}:\frac{3}{{10}}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\frac{1}{2}x - \frac{3}{4}\,\,\,\,\, = 8\,\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\frac{1}{2}x\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 8 + \frac{3}{4}\,\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\frac{1}{2}x\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{{35}}{4}\,\,\,\,\,\,\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{{35}}{4}:\frac{1}{2}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{{35}}{2}\end{array}\)
Chọn A
