does iphone 7plus earphones compatible with iphone X?

Maybe, but it would help if you provide us with what exact earphones are these "iphone 7plus earphones."

If they are not working, the support article you arrived here from should provide you with the proper troubleshooting steps to take in that case.

Ok, the iPhone 7 came with a pair of EarPods with a Lightning connector. This should work fine with an iPhone X's Lightning connector.

Sure, if the connector fits every headset is compatible