Given 2p-30= 4p+6.  First add 30 on both sides

               +30       +30

            ------          ------

 

   2p              = 4p +36.   Now  subtract 4p from both sides

 -4p                 -4p

----                 ------

-2p               = 36

 

Therefore  p= 36/(-2)

                   = -18        Answer