Answer:
Undefined.
Step-by-step explanation:
[tex]m = \frac{rise}{run} [/tex]
[tex]m = \frac{ - 15 - ( - 20)}{ - 18 - ( - 18)} \\ m = \frac{ - 15 + 20}{ - 18 + 18} \\ m = \frac{5}{0} [/tex]
The denominator is 0. Therefore, the slope is undefined.
