Any line with no slope is parallel to the

*x-axis
*y-axis
*line y = x

The x-axis.

In the form Y = mx + b

m is the slope, so no slope means that my is zero so that means x is zero also.

So you would end up with

y = b so that means y will always be that value and the only thing that will change is the x value. This will create a horizontal lines that is parallel to the x-axis

Yuh yeet honestly idk