#### Answer

Refer to the attached image below.

#### Work Step by Step

RECALL:
The point $(x, y)$ has:
$x$ = directed distance of the point from the y-axis (negative when to the left of the y-axis, positive when to the right)
$y$ = directed distance of the point from the x-axis (negative when below the x-axis, positive when above)
Thus. the set $\left\{(x, y)|x=-4\right\}$ represents the set of points that are 4 units to the left of the y-axis. These points form a horizontal line whose equation is $x=-4$.
(refer to the attached image in the answer part)