$$\left. \begin{array} { l } { y ^ { 2 } = 4 a x } \\ { x ^ { 2 } = 4 a y } \end{array} \right.$$
$\left\{\begin{matrix}\\x=0\text{, }y=0\text{; }x=4a\text{, }y=4a\text{, }&\text{unconditionally}\\x=\frac{\left(\sqrt{-3a^{2}}+a\right)^{2}}{a}\text{, }y=-2\sqrt{-3a^{2}}-2a\text{; }x=\frac{\left(\sqrt{-3a^{2}}-a\right)^{2}}{a}\text{, }y=2\sqrt{-3a^{2}}-2a\text{, }&a\neq 0\end{matrix}\right.$
$x=0\text{, }y=0$
$x=4a\text{, }y=4a$
