Minor editing suggestion in markdown

[prowe12]

In 02.02-Production-Model-Sensitivity-Analysis, in the Markdown cell after "Sensitivity Analysis", the text includes:

"Solving for $x {A_a}^{-1}b_a$"

Assuming I'm understanding the intent right, I think this is clearer if changed to:

"Solving for $x$ yields ${A_a}^{-1}b_a$, and plugging this in for $x$ in the equation for P gives"

Finally, thank you for this great Cookbook!