Linear Function

**Definition:**

A linear function is a polynomial of degree one. The graph of a linear function is a straight line. The rate of change of a linear function is called the slope of the function. In a linear function, the average and instantaneous rate of change are always the same.

**Formula for a Linear Function:**

General Form:

Slope-Intercept Form:

Point-Slope Form:

Two-Point Form:

**Linear Function Photo:**

Mr. Lee's Example Photo

Photo Description: This is a picture of the Chapel Bridge in Lucern, Switzerland that I took while on vacation. The roof of this footbridge, originally constructed in 1333, can be modeled by a linear function. I set the origin at the base of the stone tower. Given this somewhat arbitrary origin, the roof of the bridge could be modeled by the function y = 0.25x + 2.