The inequality \(p_1x_1 + p_2x_2 \leq M\) in economics, specifically within the Theory of Consumer Behaviour, is known as the Consumer's Budget Constraint. This equation mathematically defines the expenditure limits for a consumer, where:
The Budget Constraint illustrates all feasible combinations of goods \(x_1\) and \(x_2\) that a consumer can purchase without exceeding their income \(M\). Consumption choices are considered affordable if they fall on or below the line defined by this equation.