\(\left(x^3+1\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x^3+1=0\\x+2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x^3=-1\\x=-2\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-2\end{matrix}\right.\)
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