Answer:
slope = undefined
Step-by-step explanation:
The slope of a vertical line will always be undefined. The slope of a horizontal line is y = 0, because the line is not moving up or down. It is flat and constant. However, the slope of a vertical line is undefined because it has the same x-coordinate, and y = 0. This cannot happen because the slope will have a 0 in the denominator, causing it to be undefined.
