The document discusses functions and their use in business contexts. It defines a function as a rule that pairs each element in one set to a single element in another set. Functions can be represented by ordered pairs in a table or graphically. Real-life examples of functions include the price of grocery items or a company's monthly sales. The independent variable is the input to a function, while the dependent variable is the output. Functions in business are often described using equations like cost, profit, or accumulated value functions. The document also discusses different types of functions like linear, quadratic, exponential, logarithmic, and polynomial functions.