$$100-289=- { y }^{ 2 } + { x }^{ 2 }$$
$x=-\sqrt{y^{2}-189}$
$x=\sqrt{y^{2}-189}$
$x=\sqrt{y^{2}-189}$
$x=-\sqrt{y^{2}-189}\text{, }|y|\geq 3\sqrt{21}$
$y=\sqrt{x^{2}+189}$
$y=-\sqrt{x^{2}+189}$
