While linear programming (LP) has been a very useful tool developed and used by operation research, power systems, and industry, such as aerospace, for power system, it is fully used in operation and planning of determining resource allocation and value. In recent years, it is a major tool for pricing measured resources. It has been of major use in prediction and estimation of data from measurements. The chapter introduces integer programming to account for discrete decision variables. The sensitivity method that reduces computational burden by accounting for small perturbation in right-hand side variables will also be found useful to the reader. Research papers that apply LP-based optimal power flow for minimal losses, cost, etc. use LP to solve optimal operating points of voltage, power as constraints in order to determine the minimized objective values and determine the optimal objectives.