I'm not sure I understand the question. Is this worded correctly?
Answer:
|2|, |11 ¾|, |-12|, |-20.5|
Step-by-step explanation:
When you have absolute value, you basically remove the negative symbol.
I think it is -2, if that helps
Answer:
8a. 0 8b. -1/3
Step-by-step explanation:
slope formula: 
8a. => (8 + 12)/(17 - 17) = 20/0 = 0
8b. (1 + 2)/(-3 - 6) = 3/-9 = - 1/3
(a,7) lies on the equation of 5x-y=8, that means we solve for x when y=7.
5x-(7)=8
5x=8+7=15
x=3
=>
a=3