Linear programming is used to optimize problems that can be expressed as linear inequalities, equations, and constraints. It aims to find the combination of variables and values that maximizes an objective function while satisfying the constraints. Common applications include operations research problems like resource scheduling and cost-benefit analysis. An example problem maximizes profit by determining the optimal production levels of 4 products given constraints on labor, capital, and materials. The problem is expressed as linear inequalities and can be solved using methods like the Simplex algorithm.