In case you want to know more about optimization and mathematical or linear programming, here is a brief selection of printed resources:

Williams, H. P. Model Building in Mathematical Programming, 4th ed. New York: John Wiley & Sons, 1999. This textbook includes many examples of how to design mathematical models, including linear programming formulations. (How you formulate your model is at least as important as what ILOG CPLEX does with it.) It also offers a description of the branch & bound algorithm. In fact, Williams's book inspired some of the models delivered with ILOG CPLEX.

Wolsey, Laurence A., Integer Programming, New York: John Wiley & Sons, 1998. This book explains branch and cut, including cutting planes, in detail.

Nemhauser, George L. and Laurence A. Wolsey, Integer and Combinatorial Optimization, New York: John Wiley & Sons, 1999. A reprint of the 1988 edition. This book is a widely cited and comprehensive reference about integer programming.

Gill, Philip E., Walter Murray, and Margaret H. Wright, Practical Optimization. New York: Academic Press, 1982 reprint edition. This book covers, among other topics, quadratic programming.