1. Many free software mathematics packages on the Internet will solve a system of equations given the coefficients in the system.

Problem: find out which of the four techniques (the Method of Addition, the Method of Substitution, Gauss-Jordan Elimination, and Cramer's Rule) is used in the majority of these types of software packages. Give your opinion why this technique is the one most commonly used. I am not sure about this one.

2. Three foods have the following nutritional content per ounce.
Calories, Protein (in grams), Vitamin C (in milligrams)

Food A 40calories,5 protein grams,30vitamin C in miligrams
Food B 200calories,2 protein grams,10 vitaminC in miligrams
Food C 400calories,4 protien grams,300 vitaminCinmiligrams

If a meal consisting of the three foods allows exactly 660 calories, 25 grams of protein, and 425 milligrams of vitamin C, how many ounces of each kind of food should be used?