the second picture is the queation i want the first is only the experiment for picture 2

A solution of phenolphthalein has been analyzed by absorbance spectroscopy. The el for the spectrophotometer was determined to be 7695 M-1. If the absorbance of the solution is 0.279 what is the phenolphthalein concentration ([Ph2-1, M)? In this experiment corrected integrated rate laws are used to account for excess This equilibrium reaction has a Ke