Is the difference between the two reallt that important? If so,why don't algebra books clarify the differences? Dr. Etgen, a professor of mathematics at the university of houston notes that "it's not until you get to linear algebra (linear transformations), differential equation (linear differential operators), and beyond, that the precise definition is needed."
still, i believe that it is beneficial to study the strict definitions and apply them to the slope-intercept form of a linear equation in order to examine what constitutes a linear function.
when learning about linear equations and linear functions, an Algebra i student is often asked the following question : Is y = x . a linear functionM it is a good starting question for my study.