7.26. A cereal manufacturer wants to make a new brand of cereal combining two natural grains x1 and x2 The new cereal must have a minimum of 128 units of carbohy- drates, 168 units of protein, and 120 units of fructose. Grain 1 has 24 units of carbohydrates, 14 units of pro- tein, and 8 units of fructose. Grain 2 has 4 units of carbo- hydrates, 7 units of protein, and 32 units of fructose. Grain 1 costs $7 a bushel, grain 2 costs $2. Express the data in equations and inequalities amenable to finding the least-cost combination of grains that will fulfill all the nutritional requirements