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 $y=2$.