The equation "y = mx + b" represents a linear function in mathematics. In this equation, y is the dependent variable, x is the independent variable, m is the slope of the line, and b is the y-intercept. The slope indicates how steep the line is, while the y-intercept shows where the line crosses the y-axis. This formula is commonly used in various fields, including economics, physics, and engineering, to model relationships between two variables. By adjusting the values of m and b, one can create different lines that represent different scenarios or trends in data.