$$\left. \begin{array} { l } { x ^ { 2 } + y ^ { 2 } = 12 x - 30 } \\ { \right.$$
$x=\sqrt{6-y^{2}}+6$
$x=-\sqrt{6-y^{2}}+6$
$x=\sqrt{6-y^{2}}+6$
$x=-\sqrt{6-y^{2}}+6\text{, }|y|\leq \sqrt{6}$
