Answer
$y=2$
Work Step by Step
If a line is parallel to another they have the same slope.
For a horizontal line, the equation comes in the form of $y=a$, where $a$ is a constant.
The line is said to be parallel to,$y=5$, which is a vertical line.
A line that is parallel to a vertical line is also vertical.
The vertical line we are looking for contains the point $(4, 2)$ whose $y$-coordinate is $2$.
This means that the equation of the line must be $y=2$.
