Answer:
y = e^(-1/2x -1)
Explanation:
You want the equation for y(x), which is graphed as a straight line on a semi-log scale.
Graph
Let z = ln(x). The graph shows a straight line with a z-intercept of -1 and a slope of "rise"/"run" = -1/2. That means the slope-intercept equation for this line can be written as ...
z = -1/2x -1
Equation
Using z = ln(y), we can find the equation for y by taking antilogs:
ln(y) = -1/2x -1
y = e^(-1/2x -1)
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Additional comment
The attached graph shows y = f(x) and the line ln(y).