Hello:
Okay, this problem should be taken in a series of steps:
What is the slope's formula?
- (x₁,y₁) -- first point
- (x₂,y₂) -- second point
Okay, now let's use this knowledge
10. (5,-19) and (-5,21)
11. (12,1) and (12, -1)
12. (8,7) and (4,7)
Answer:
- Question 10: -4
- Question 11: undefined
- Question 12: 0
Hopefully that helps!