Answer:
-3
Step-by-step explanation:
c is y when x = 0
At x = 3, y = 21-9 = 12
At x = 2, y = 12 - 7 = 5
At x = 1, y = 5 - 5 = 0
At x = 0, y = 0 - 3 = -3
c = -3
b
