Main Page | See live article | Alphabetical index The term linear function is sometimes used for a function of the form f(x) = ax + b, because the graph of a function of that form is a line. Functions of that form are affine transformations, and are thus called affine functions in some texts. They are linear transformations if and only if b = 0. See also Polynomial. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.