<PRE><B>Question 554813</B>
m = (-6-9)/(-12-(-12)


m = -15/0


Let m = slope


Since we cannot divide by zero, then the answer is UNDEFINED SLOPE. 


This means, the slope DOES NOT EXIST for the given two points.


The line that connects the two given points is surely a vertical line for the slope of vertical lines does not exist. The line that connects these two points is the line x = -12, which is a vertical line.  




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