[tex]\bf \begin{cases}
x=-1\implies &x+1=0\\
x=0\implies &x=0
\end{cases}
\\\\\\
\stackrel{\textit{multiplicity of 3}}{(x+1)^3}~~\stackrel{\textit{multiplicity of 1}}{(x)^1}=\stackrel{original~polynomial}{0}
\\\\\\
(x^3+3x^2+3x+1)(x)=\stackrel{y}{0}\implies x^4+3x^3+3x^2+x=y[/tex]
