$$\left. \begin{array} { l } { y _ { 1 } x _ { 1 } = \frac { 1 } { x _ { 1 } } y = 50 y _ { 1 } y y x = - } \\ { \text { a n i s a \right.$$
$\left\{\begin{matrix}x_{1}=-y_{1}^{-\frac{1}{2}}\sqrt{y}\text{; }x_{1}=y_{1}^{-\frac{1}{2}}\sqrt{y}\text{, }&y\neq 0\text{ and }y_{1}\neq 0\\x_{1}\neq 0\text{, }&y=0\text{ and }y_{1}=0\end{matrix}\right.$
$\left\{\begin{matrix}x_{1}=\sqrt{\frac{y}{y_{1}}}\text{; }x_{1}=-\sqrt{\frac{y}{y_{1}}}\text{, }&\left(y_{1}<0\text{ and }y<0\right)\text{ or }\left(y_{1}>0\text{ and }y>0\right)\\x_{1}\neq 0\text{, }&y=0\text{ and }y_{1}=0\end{matrix}\right.$
