Does the Inspiron 5579 2-in-1 support external graphics through USB?

@guilhermekehl  no, that's not possible.  A GPU has to interface with the system over PCI Express, and you can't run PCI Express traffic over a regular USB port.  The two most common ways to do this are to use Thunderbolt 3 or else use a proprietary connector like the Alienware Graphics Amplifier connector if you have an Alienware system that has one.  The only other way is to install an M.2 or Mini-PCIe card internally in your system that has a flat ribbon cable that literally has to stick out of your system, and then connect an eGPU enclosure to that.  However, in addition to the fact that this solution is a bit ugly, most systems don't have a spare Mini-PCIe or M.2 slot.  They typically only have one slot that's used by the WiFi card.  And even if you'd be willing to give up WiFi and deal with having a ribbon cable sticking out of your system, your system might only have a PCIe x1 interface wired to that slot.  Thunderbolt 3 offers a PCIe x2 or x4 interface, depending on the system, and the Alienware Graphics Amplifier I believe offers a full PCIe x8 or x16 interface.