Answer
$\color{blue}{x=4}$
Work Step by Step
RECALL:
(1) A line whose equation is of the form $x=h$ is a vertical line whose x-intercept is $h$. All points on this line have an x-coordinate $x=h$.
(2) Vertical lines are parallel to each other.
The line we are looking for is parallel to the vertical line $x=5$,
This means that its equation is of the form $x=h$, and that every point on the line has an x-coordinate $x=h$.
The line contains the point $(4, 2)$.
Since the x-coordinate of this point is $4$, the equation of the line is:
$\color{blue}{x=4}$
