There are three different relationships between x and y.
Function I represents a straight line consisting of a set of ordered pairs such as (3,4),(4,5), and (7,8).
Function II:
Input (x)Output (y)0612301842
Function III: It represents a straight line having a slope greater than the slope of each function I and II, but the y-intercept is greater than that of function I and less than that of function II.
The equation of function III can be _______ .