Q:  Write an equation of the form

                M(V)  =   _________ * log(P)   +    ___________

         which is consistent with the data in the graph.


             Looking at the line drawn on the diagram, I can pick out
             the endpoints

                     (0.6, -3.0)        and     (2.0, -6.5)

             The slope of the line connecting them is approximately

                                (-6.5 - (-3.0) )       -3.5
                      slope  =  ----------------  =   -------  =  -2.5
                                ( 2.0 -  0.6   )        1.4
              

             If we plug into the equation

                       -3.0  =  (-2.5 * 0.6)  +   X

             and solve for "X", we can find the y-intercept.  It turns out

                         X   =  -1.5

             So the relationship between period and absolute magnitude
             is approximately

                          M(V)  =  -2.5 * log(P)  -  1.5