Answer
$a.\quad x=0$
$b.\quad y=-\sqrt{2}$
Work Step by Step
$ a.\quad$
Vertical lines contain points $(x,y)$ that all have the same x-coordinate.
Given that $(0, -\sqrt{2})$ lies on the line and has its x-coordinate equal to $0$, the vertical line has the equation
$x=0$
$b.\quad $
Horizontal lines contain points $(x,y)$ that all have the same y-coordinate.
Given that $(0, -\sqrt{2})$ lies on the line and has its y-coordinate equal to $-\sqrt{2}$, the horizontal line has the equation
$y=-\sqrt{2}$
