Hi @albert123456780 ,
Have you checked the audio settings in the laptop, to ensure that the “balance” is not set to just one speaker, left or right?
If the audio settings are OK and you only get audio through one headphone speaker, when using different headphones, then It seems as though there may be a problem with the audio socket in the laptop.
Is the laptop still covered by the manufacturer’s warranty? If it is consult the warranty as to what to do to make a claim for a manufacture’s warranty repair or replacement.
If the laptop is no longer covered by the manufacturer’s warranty, here’s a link to the service manual for the laptop. Scroll to p.13 to view the necessary pre-requisite steps and then the procedure to remove/replace the audio board. The audio board is available online. Just search for Dell 11 3180 Chromebook Audio Board part to get results for suppliers of the part.