Đặt \(\sqrt[3]{6x+4}=a\Rightarrow6x=a^3-4\)
\(\Rightarrow\left\{{}\begin{matrix}x^3=6a+4\\a^3=6x+4\end{matrix}\right.\) \(\Rightarrow x^3-a^3+6\left(x-a\right)=0\)
\(\Leftrightarrow\left(x-a\right)\left(x^2+ax+a^2\right)+6\left(x-a\right)=0\)
\(\Leftrightarrow x=a\Leftrightarrow x=\sqrt[3]{6x+4}\)
\(\Leftrightarrow x^3-6x-4=0\)
\(\Leftrightarrow\left(x+2\right)\left(x^2-2x-2\right)=0\)