I got the following absorbance for 3 unknown protein samples: -0.019, 0.019, -0.22 and I need to calculate their concentration. The equation for the line in the graph is y= .83x + 0.1226. I do not know if I use this equation or the beer's law ( I do not know how to use the beer's law ) or the equation of the line to calculate concentration. Also I am not the negative values are right and how I calculate them. Your help is appreciated.