\(2x^2+2y^2+z^2+2xy+2xz+2yz+10x+6y+34=0\)
\(\Rightarrow\left(x^2+y^2+z^2+2xy+2xz+2yz\right)+\left(x^2+10x+25\right)+\left(y^2+6y+9\right)=0\)
\(\Rightarrow\left(x+y+z\right)^2+\left(x+5\right)^2+\left(y+3\right)^2=0\)
Vì \(\left\{{}\begin{matrix}\left(x+y+z\right)^2\ge0\\\left(x+5\right)^2\ge0\\\left(y+3\right)^3\ge0\end{matrix}\right.\)
\(\Rightarrow\left(x+y+z\right)^2+\left(x+5\right)^2+\left(y+3\right)^2\ge0\)
Mà \(\left(x+y+z\right)^2+\left(x+5\right)^2+\left(y+3\right)^2=0\)
\(\Rightarrow\left\{{}\begin{matrix}\left(x+y+z\right)^2=0\\\left(x+5\right)^2=0\\\left(y+3\right)^2=0\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x+y+z=0\\x+5=0\\y+3=0\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}z=-\left(x+y\right)\\x=-5\\y=-3\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}z=8\\x=-5\\y=-3\end{matrix}\right.\)
