Cho \({\left( {2{\rm{x}} +...

B

- Hướng dẫn giải

\(\begin{array}{l}{\left( {2{\rm{x}} + 1} \right)^3} = - 8 \Leftrightarrow {\left( {2{\rm{x}} + 1} \right)^3} = {\left( { - 2} \right)^3}\\ \Leftrightarrow 2{\rm{x}} + 1 = - 2 \Leftrightarrow x = - \frac{3}{2}\end{array}\)