Answer:
The slope is undefined because it's a vertical line.
Explanation:
The slope of the line passing through the points (x1,y1) = (-7,0) & (x2,y2)=(-7,-6)
Recall the slope of the line equation :
m = (y2-y1)/(x2-x1)
Thus m = (-6-0)/((-7)-(-7)) => (-6)/0 => the slope is undefined because of the 0 in the denominator. It's a vertical line.
When you have a vertical line, your slope is undefined