For instance assume that x ilv has y amount of secondary stat budget. This means that you could have y = 1 secondary stat (i.e. haste) or y = 2 secondary stat (i.e. z haste and b-y mastery). Since there are five secondaries, you could get 1 of 15 different combinations:
Pure Haste Pure Mastery Pure Crit Pure Multistrike (MS) Pure Versatility (Vers?) Haste/Mastery Haste/Crit Haste/MS Haste/Vers Mastery/Crit Mastery/MS Mastery/Vers Crit/MS Crit/Vers MS/Vers
The above table is only for Armor pieces excluding cloaks, rings, necklaces, trinkets and weapons. Those apparently can have additional secondaries.