lmax or 1max ?? 1. The problem statement, all variables and given/known data I have a graph of concentration vs Absorbance like below, for PNP. http://img512.imageshack.us/img512/2614/pnpgraphexfa7.jpg [Broken] problem is that I have to find the unknown concentration, so I use the graph to determine that. The equation to find it is y= mx what I don't understand is when they say that the y used is: y= 1max Is it the maximum point on the graph? m= slope x= concentration of PNP Can someone tell me what I put for y= 1max so I can find the concentration? I have the slope, but that's the only thing that is confusing me. Thank you!