A feasible area for each constraint (except for the nonnegativity constraints) is determined
by everything that lies below (or to the left of) the resulting line. The feasible
set or region is the intersection of each constraint’s feasible area. The feasible set is
shown by the figure ABCD in the exhibit; it includes the boundary of the figure. Notice
that only two of the five constraints qualify as candidates for binding constraints:
the drilling and polishing constraints