affine functions

A function is affine if it has this algebraic expression: y = f(x) = mx + n (m,n  € R), with a polynomial of degree 0 or 1.

Its graph is a straight line, where m is called slope and n is called y-intercept.

- If m > 0 the function is increasing

- If m < 0 the function is decreasing

Example: f(x) = 3x + 2
                               3 is the slope and 2 the y-intercept