You must use the slope formula to find out what the slope is between the lines. The slope formula is: (y2 - y1)/(x2 - x1). Plug in the points to get your answer.
You have the points (-3, -2) and (-3, 6). The x-coordinates are -3 and -3 while the y-coordinates are -2 and 6.
(6 - (-2)/(-3 - (-3))
8/0
You cannot divide by zero, so the slope is undefined. This means the line that the points both fall on is a vertical line and is unable to have a slope.
