Answer:
c. (9, 9)
Step-by-step explanation:
When numerous inequalities are involved, I like to graph them with the inequality symbol reversed. This leaves the solution set as a white space on the graph, instead of it having multiple overlays.
The vertices of the solution set for these inequalities are (3, 6), (4, 2), and (9, 9).
The maximum of the objective function will be found at one of these vertices. Since the coefficients in the objective function are both positive, we expect the maximum value to be found at the vertex that is farthest from the origin when measured perpendicular to the line f(x, y) = 0. That vertex is (9, 9).
The maximum is at (9, 9).
