Đáp án đúng: D
Giải chi tiết:\(\begin{array}{l}\,\frac{{{x^2}}}{{ - 2}} = \frac{8}{{2x}} \Leftrightarrow \frac{{{x^2}}}{{ - 2}} = \frac{4}{x}\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \Rightarrow {x^3} = - 2.4\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \Leftrightarrow {x^3} = - 8\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, \Leftrightarrow x\,\,\, = - 2\end{array}\)
Vậy \(x = - 2\)
Chọn D