What is "this mapping shows a functional relationship. when f(x)=4?

When a mapping shows a functional relationship, it means that there is a clear and specific relationship between the input and output values. In the case of the given statement, when f(x) = 4, it means that for every input value x, the output value f(x) will always be equal to 4.

This implies that the function f(x) is a constant function, where the output value is the same for all possible input values. This can be represented graphically as a horizontal line at y = 4 on a coordinate plane.

In mathematical terms, the functional relationship can be expressed as f(x) = 4 for all values of x. This means that the function f(x) assigns the value of 4 to any input value x.