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
Answer: $7
Step-by-step explanation: if a stapler cost $3, then 20staplers will cost $60
Amount left will be $200-60=$140
Cost of one organiser will be $140/20
That will be $7
between 3 and 4 would be 3.5cm