Given:
The function is
To find:
The rate of change of the given function.
Solution:
We have,
...(i)
It is a linear function because the degree or power of x in this function is 1.
Slope of a linear function is always constant.
The slope intercept form of a linear function is
...(ii)
where, m is slope and b is y-intercept.
On comparing (i) and (ii), we get
It means, the function has a constant rate of change, decreasing for all x at a rate of 5.
Therefore, the correct option is D.