Of course you can!  He is thinking about running tren and  deca together since the line of thought is you do not want to run two Nandrolones together.... but I still known people that do - go figure.  
Please read up on why you should not run two nandro's together.
my opinion:
Test, Eq, and tren is okay choice for compounds to run but I wouldn't really pair eq with tren.  To me a better combo might be Test, Eq and Npp.  Just my opinion though