A:AnswerThe Lenovo Yoga C640-13 model number 81UE001PUS, uses a USB-c 3.2 version port with video out capability for connecting an external monitor. You can connect an HDMI based external monitor to this laptop by using a USB-c to HDMI adapter like this one: https://www.bestbuy.com/site/belkin-usb-type-c-to-hdmi-usb-type-c-cable-black/6409317.p?skuId=6409317
A:AnswerNo. The 8GB of DDR4-2400MHz RAM is soldered to the motherboard and is not upgradeable. Here is a link to more information about this model: https://psref.lenovo.com/Detail/Yoga/Yoga_C640_13IML?M=81UE001PUS
A:AnswerThe Lenovo Yoga C640-13 model number 81UE001PUS, ships with the 4-Core/8-Thread Intel Core i5-10210U processor, with a base speed of 1.6GHz and a Turbo Boost Speed of up to 4.2GHz.
A:AnswerThis model, the Lenovo Yoga C640-13, model number 81UE001PUS, ships with a IPS LCD w/LED Backlight (Anti-glare) screen, with a resolution of 1920 x 1080 (FHD) and a brightness level is 300 nits.