A.8.A Quadratic Equations

A college student needs 11 classes that are worth a total of 40 credits in order to complete her degree. The college offers both 4-credit classes and 3-credit classes. Which system of equations can be used to determine f, the number of 4-credit classes the student can take to complete her degree, and h, the number of 3-credit classes?

A new spiral notebook contains 30 more sheets of paper than a new memo book. The total number of sheets of paper in 3 new spiral notebooks and 5 new memo books is 810. Which system of equations can be used to find s, the number of sheets of paper in one new spiral notebook, and m, the number of sheets of paper in one new memo book?

The owner of a clothing store buys T-shirts for c dollars each and sells them for p dollars each. Last month she bought 600 T-shirts and sold 500 of them and made a profit of $2,800. This month she bought 400 T-shirts and sold them all and made a profit of $2,400. Which system of equations can be used to determine the values of c and p?