Great! Based on the output pairs you provided, it seems that the function f(x) is a non-linear transformation that takes a numerical input x and returns an output that is approximately linear with a positive slope.

Here is a simple description of the function:

[DESCRIPTION] f(x) takes a numerical input x and returns an output that is approximately linear with a positive slope.

[DOMAIN] The domain of the function is the set of all real numbers.

[CODE] Here is some python code that approximates the behavior of the function:

def f(x):
return 2*x + 1

This code defines a simple linear function with a positive slope that maps the input x to the output f(x).

Let me know if you'd like to test any other input values or if you have any questions!