Vertical lines have slopes which are undefined.
----- = slope For a vertical line, it is all rise and no run. Such as 5/0 or 3/0 or 128/0.
When you divide by zero, it is considered undefined.
Therefore, the slope of x = 5 is undefined.
Also, since it is a vertical line, passing through 5 on the x-axis,
there is no y-intercept.
slope = undefined
Below, is the graph of x = 5.
- Algebra House