Functions

Functions:

    A function is a fundamental concept in mathematics, often described as a "black box" that processes an input to produce a corresponding output. You don't necessarily need to understand the internal workings of a function to use it—simply provide an input, and the function will return the appropriate output.

Example:
    f(x) = y
In this example, x is the input (independent variable), and y is the output (dependent variable) produced by the function f.

Consider the function:
    f(x) = 2x + 5

To evaluate the function for x = 5:
    f(5) = 2 × 5 + 5
            = 10 + 5
            = 15

Therefore, f(5) = 15.