A one-to-one function with the set of all points in the plane as the domain and the range is called transformation. A function transformation takes whatever is the basic function f (x) and then "transforms" it (or "translates" it), which is a fancy way of saying that you change the formula a bit and thereby move the graph around. Moving the function down works the same way; f (x) – b is f (x) moved down b units.