Math
posted by Anne .
Find the slope of the secant line on f joining the points at x = e and x = 2e.

The slope will depend upon the y values at x = e and x = 2e.
I have no idea what you mean by "the secant line on f"
You must have omitted a figure, or other parts of the question. 
A secant line of a curve is a line that (locally) intersects two points on the curve.
You must know equation of curve f(x) if you want to find secant line.