Answer:
a. 0
Step-by-step explanation:
1. To find the slope given two points, use the following formula:

2.
would be the second y-value (in the second ordered pair), 2, and
would be the first y-value (in the first ordered pair), also 2.
3. Same for the x-values.
is -2 and
is 4
4. Now plug in the values.

5. This equals
which simplifies to 0