Look at step 1, - 6 + 6 = 0
3+6=9
Answer:
Step-by-step explanation:
(x₁, y₁) = (19 , -4) & (x₂ ,y₂) = (17, -20)

![= \frac{-20-[-4]}{17-19}\\\\= \frac{-20+4}{17-19}\\\\= \frac{-16}{-2}\\\\= 8](https://tex.z-dn.net/?f=%3D%20%5Cfrac%7B-20-%5B-4%5D%7D%7B17-19%7D%5C%5C%5C%5C%3D%20%5Cfrac%7B-20%2B4%7D%7B17-19%7D%5C%5C%5C%5C%3D%20%5Cfrac%7B-16%7D%7B-2%7D%5C%5C%5C%5C%3D%208)
m = 8
Parallel lines have same slope.
Parallel slope = 8
Slope of perpendicular line = 
Perpendicular slope = 
3/10 can stay the same,
2/5 >>
2*2 = 4
5*2 = 10
4/10 and 3/10
You have to turn the 12 into 1/12 for its reciprocal. Then you do 4/9*1/12. You cancel the 4 and make it into a 1 and make the 12 into a 3. 9*3=27. So you get D: 1/27
C. Never
This is because they should be parallel if the are two separate rays.