my mac starts beeping when i turn it on and the screen remains black

It doesn't matter if you added any recently; RAM can fail (although not often, but it can).

The beeps appear to indicate a problem with RAM, so if the RAM slots are accessible, you can test it by removing all but one > then do the next one > etc. until you can figure out which slot and/or which module is faulty. Then contact Apple support.

That may have a couple of causes - one of them would be RAM - either a bad module or the slot may be bad. Did you recently add more RAM?

https://support.apple.com/en-us/HT202768

You thinK? If you did add RAM I think you would know. It's an important question.