Q:  What is the mass of the object at the center of M84?



                   (4 x 10^5 m/s)^2  *  (2.5 x 10^(17) m)
          M   =   -----------------------------------------
                          6.67 x 10^(-11) N*m^2/kg^2


              =    5.9 x 10^(38)  kg

              
              =    3  x 10^8      solar masses