$x=\frac{\sqrt{8y+169}+11}{4}$
$x=\frac{-\sqrt{8y+169}+11}{4}$

$x=\frac{\sqrt{8y+169}+11}{4}$
$x=\frac{-\sqrt{8y+169}+11}{4}\text{, }y\geq -\frac{169}{8}$

$y=\left(x-6\right)\left(2x+1\right)$