a: (18 - x) / 3 > 2 * x - 1
b: (18 - x) / 3 > x^(2) - 4
c: 2 * x - 1 > x^(2) - 4
d: 2 * x - 1 > (18 - x) / 3
e: x^(2) - 4 > 2 * x - 1
f: x^(2) - 4 > (18 - x) / 3
A = Point(f)
B = Point(c)
C = Point(f)