Answer:
Step-by-step explanation:
a=-7
r=21/-7=-3

Answer: 6y^(3) - 19y
Step-by-step explanation:
Answer:
None of them.
Step-by-step explanation:
People with self-control are not easily described.
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