$$(x^{2}+y^{2})dx-2xydy=0$$
$\left\{\begin{matrix}\\d=0\text{, }&\text{unconditionally}\\d\in \mathrm{C}\text{, }&x=-y\text{ or }x=y\text{ or }x=0\end{matrix}\right.$
$\left\{\begin{matrix}\\d=0\text{, }&\text{unconditionally}\\d\in \mathrm{R}\text{, }&|x|=|y|\text{ or }x=0\end{matrix}\right.$
$\left\{\begin{matrix}\\x=y\text{; }x=0\text{; }x=-y\text{, }&\text{unconditionally}\\x\in \mathrm{C}\text{, }&d=0\end{matrix}\right.$
$\left\{\begin{matrix}\\x=y\text{; }x=0\text{; }x=-y\text{, }&\text{unconditionally}\\x\in \mathrm{R}\text{, }&d=0\end{matrix}\right.$
