Examples of linear functions used in real life include calculating equal conversions for currency rates or units, determining the length of time or distance traveled for a trip, increasing measurements for a recipe to increase the product and estimating the number of bricks needed to build a certain size wall. Any function where an increase or decrease in input causes the exact change in the output is a linear function.
Linear functions are mathematical equations with a relationship between two quantities, where the rate of change is constant. Linear functions produce a graph that forms a straight line, and they have many applications in which the two variables represent items in the real world. In business, the linear function for profit is revenue minus cost, and if the revenue increases, the profit increases by the same amount.
Linear functions are used to predict or estimate outcomes such as the amount of shirts produced at a factory in 10 days when it is known how many are made in one day. They're used in modeling scenarios such as how many crops will be needed in ten years based on how many are needed today. Columbia University mentions that economists often look at the rate of change in linear function modeling because it is important to consider how one item changes in response to a change in another item.