Answer
$a.\quad x=-1$
$b.\displaystyle \quad y=\frac{4}{3}$
Work Step by Step
$ a.\quad$
Vertical lines contain points $(x,y)$ that all have the same x-coordinate.
Given that $(-1, \displaystyle \frac{4}{3})$ lies on the line and has its x-coordinate equal to $-1$, the vertical line has the equation $x=-1$
$b.\quad $
Horizontal lines contain points $(x,y)$ that all have the same y-coordinate.
Given that $(-1, \displaystyle \frac{4}{3})$ lies on the line and has its y-coordinate equal to $\displaystyle \frac{4}{3}$, the horizontal line has the equation $y=\displaystyle \frac{4}{3}$
