So far you have mostly worked with equations. there are special types of equations, called functions, that have exactly one output for every possible input into the equation. an example of this in the real world is the amount of money you are charged at a store: the input is the item you are purchasing, and the output is the money you are charged. individual items have one price, so this is an example of a function. can you think of any other examples of functions? why might this type of equation be useful?

The idea of a function in simplest of words can be defined as a machine where an input goes in, some process is done inside the machine and an output comes out.

To understand this, we can take a real life example of a vending machine. The user puts in the money (or the card with credit in it), punches a specific button for what he wishes to take out and then that the selected item is dropped into the output slot.

Here the input will be the money (or card) along with the selection of the item, the output will be the product and the price of that product will be the function rule.

answer: the answer is 23

step-by-step explanation: