Give the definition of the function. What is called the scope and scope of a function?

The variable y is a function of the variable x, if such a relationship is set between these variables, which allows for each value of x to unambiguously determine the value of y.
The domain of a function is the set of all possible values of the variable x.
The range of values of a function is the set of all values of y, determined by the number x from the range of definition of the function, according to the specified rule.
Example of a function: linear function y = kx + b;
The domain of definition, as well as the domain of meaning, is the set of all numbers.