$$y = 2 x ^ { 2 } + 4 x$$
$x=-\frac{\sqrt{2y+4}}{2}-1$
$x=\frac{\sqrt{2y+4}}{2}-1$
$x=-\frac{\sqrt{2y+4}}{2}-1$
$x=\frac{\sqrt{2y+4}}{2}-1\text{, }y\geq -2$
$y=2x\left(x+2\right)$
