Can I upgrade the RAM on my HP Pavilion Elite HPE-112y
Yes it currently has 8 gigs then.
This system can be upgraded to16 gigs, but you may have difficulty aquiring the RAM as its been discontinued.
A good way of solving this class of problem is to go to the Kingston or Crucial website and search for memory for your specific device - it usually advises the valid memory configurations and even exact supported memory modules.
https://www.kingston.com/us/memory/search/discontinuedmodel/61982/hp-compaq-pavilion-elite-hpe-112y provides the details for your systems memory.