ĐK x≤16/5.
\(\Leftrightarrow\left\{{}\begin{matrix}x^2+4x+4+y-4=0\\\left(x+2\right)^4+5y=16\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\left(x+2\right)^2=4-y\\\left(x+2\right)^4+5y=16\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(x+2\right)^2=4-y\\\left(4-y\right)^2+5y=16\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\left(x+2\right)^2=4-y\\y^2-3y=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(x+2\right)^2=4-y\\\left[{}\begin{matrix}y=0\\y=3\end{matrix}\right.\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}y=3\\\left(x+2\right)^2=4-3\end{matrix}\right.\\\left\{{}\begin{matrix}y=0\\\left(x+2\right)^2=4\end{matrix}\right.\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}y=3\\\left[{}\begin{matrix}x+2=1\\x+2=-1\end{matrix}\right.\end{matrix}\right.\\\left\{{}\begin{matrix}y=0\\\left[{}\begin{matrix}x+2=2\\x+2=-2\end{matrix}\right.\end{matrix}\right.\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}y=3\\x=-1\end{matrix}\right.\\\left\{{}\begin{matrix}y=3\\x=-3\end{matrix}\right.\\\left\{{}\begin{matrix}y=0\\x=0\end{matrix}\right.\\\left\{{}\begin{matrix}y=0\\x=-4\end{matrix}\right.\end{matrix}\right.\)
