The points (3, 8) and (6, 8) are part of the solution set of a quadratic inequality, while(5, 9) and (7, 7) are not. The point that must also be part of the solution set is
A. (4, 7)
B. (4, 9)
C. (8, 6)
D. (6, 10)
C?
since f(3) = f(6) = 8,
D says that y > 8, so must be above the graph.