Answer Happy

Problem 4. In order to treat a certain bacterial infection, a combination of two drugs is used. Studies have shown that the duration of the infection in laboratory tests can be modeled by T x2 + 2y2 – 18x – 24y + 2xy + 120 where x is the dose of the first drug (in hundreds of milligrams) and y is the dose of the second drug (also in hundreds of milligrams). How much of each drug should be used if we want to minimize the duration of the infection. Justify that your answer is at least a local minimum.