\(\sqrt[3]{x^3+8}=x+2\)
\(\Leftrightarrow x^3+8=\left(x+2\right)^3\)
\(\Leftrightarrow x^3+8=x^3+6x^2+12x+8\)
\(\Leftrightarrow6x^2+12x=0\)
\(\Leftrightarrow6x\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-2\end{matrix}\right.\)
Vậy \(S=\left\{0;-2\right\}\)