Yes you can. But you have to buy a power supply also. For power up external gpu.

‍yp you can use an external gpu for laptops. there are two different ways to connect gpu to laptops. 1st one is by a thunderbolt cable.

main high performance ultra books which have huge processing power without?with low performance gpu s have a thunderbolt cable. it has a huge bandwidth so reputed manufactures creates external gpu encloses that can connect laptop by a thunderbolt cable. after connecting it the gpu get the all graphic information and process them. but for connect that the laptop must has a thunderbolt port

the laptops that don't have thunderbolt ports can be connected to a external gpu via a unbranded devices. it has a pci express slot and the device connect to the wireless network card slot. so you should remove the wireless network card also. and the external gpu need a extra powers supply to power it up. soo i don't recommend that way. because if device has a malfunction or if you do any wrong the whole laptop will break