An equation of a line is:

where k is the y-intercept and b is the slope. Our equation of the blue line in the plot below is:

implying that b*log(a) is the y-intercept and b is the slope of the line. Recall that the slope of the line is 10.0 and the y-intercept is -26.1. b is therefore 10.0 and a is 0.0025 by:
Let's add this information to our power relationship.