A farmer can buy two types of plantfood, mix A and mix B. Each cubic yard of mix A contains 42

42 pounds of phosphoricacid, 18

18 pounds ofnitrogen, and 6

6 pounds of potash. Each cubic yard of mix B contains 14

14 pounds of phosphoricacid, 27

27 pounds ofnitrogen, and 24

24 pounds of potash. The minimum monthly requirements are 630

630 pounds of phosphoricacid, 810

810 pounds ofnitrogen, and 360

360 pounds of potash. Find the set of feasible solutions graphically for the amounts of mix A and mix B that can be used.

If x is the number of cubic yards of mix A used and y is the number of cubic yards of mix Bused,