A linear function is an algebraic equation in which each term is either a constant or the product of a constant and (the first power of) a single variable. For example, a common equation,
y
=
m
x
+
b
, (namely the slope-intercept form, which we will learn more about later) is a linear function because it meets both criteria with
x
and
y
as variables and
m
and
b
as constants. It is linear: the exponent of the
x
term is a one (first power), and it follows the definition of a function: for each input (
x
) there is exactly one output (
y
). Also, its graph is a straight line.
