### Theory:

In this lesson, you will learn the concepts that you should know about a line that is parallel to the $$x$$-axis or $$y$$-axis of the coordinate plane.
Line parallel to the $$x$$-axis
The $$y$$-coordinate of each point is $$0$$ on the $$x$$-axis. Therefore, we can also say that every point on the $$x$$-axis is of the form $$(x, 0)$$.
For a line that is parallel to the $$x$$-axis, the equation for such a line is $$y = b$$, where $$b$$ is the value of the $$y$$-coordinate of any point on the line.
Example:
1. If $$b = 2$$, then the equation of the line parallel to the $$x$$-axis will be $$y = 2$$.

2. If $$b = -3$$, then the equation of the line parallel to the $$x$$-axis will be $$y = -3$$. Line parallel to the $$y$$-axis
The $$x$$-coordinate of each point is $$0$$ on the $$y$$-axis. Therefore, we can also say that every point on the $$y$$-axis is of the form $$(y, 0)$$.
For a line that is parallel to the $$y$$-axis, the equation for such a line is $$x = a$$, where $$a$$ is the value of the $$x$$-coordinate of any point on the line.
Example:
1. If $$a = 1$$, then the equation of the line parallel to the $$y$$-axis will be $$x = 1$$.

2. If $$a = -2$$, then the equation of the line parallel to the $$y$$-axis will be $$x = -2$$. 