Blank RAM type for Samsung laptop

Hi, I've purchased my laptop in 2020, a Samsung E20. I had trouble on determining whether it supports DDR4 RAMs or not. I purchased a new RAM that is said to be compatible with NP350XBE laptop. When I replace the RAM, the laptop doesn't start. When I put back my old RAM, the laptop still keeps working. Is it possible to safely try combining the two RAMs in this case to see if it works?

I've posted my problem earlier on StackExchange, where I described all trouble I'm passing by:

https://superuser.com/q/1709927