"Closing the recent applications."に関する回答On the bottom left corner of your screen there should be (from left to right) back button, home button, recent apps button ( should look like a rectangle with a partial border). Tap the recent apps button. Your recent apps should be displayed. Swipe left or right on the app widows to close the individual apps or tap "remove all" at the bottom to close all recent apps.
"Red X on battery sign...?! Won't charge!"に関する回答Samsung tablets are nutorious for needing the correct power adapter (block) in order to charge. You will find that in some cases the tablet is charging even if the red x is present. Plug your device into the desired power adapter and wait an hour. Next look at your battery percentage. If the battery has charged fast enough for your standards than keep it. But if its charging really slow or not at all then I'd suggest getting a new power adapter. I would suggest getting one from amazon.com. in order to ensure that you buy the correct power adapter, look on your old power adapter to see what the model number is and match it to the one you want to purchase. If you dont have the old power adapter then search for "(device model #) power adapter" To find your devices model number go to: Settings/about device/model number When looking on amazon make sure that the power adapter you are going to purchase says that it is for your device. Sometimes there are products for different devices in the search results.
"Why I dont have option to show battery percentage?"に関する回答I'm not sure if you've already tried this but on most Samsung Galaxy devices the path to toggle the battery percentage on the taskbar is: Settings/Battery/Show battery percentage (it should be a check box) If this doesnt help could you please respond with: what software is your device running? Is it rooted? What is your carrier? Where have you looked for the "show battery percentage option?"
"Why does my device not turn on?"に関する回答There are several reasons for a device not turning on or not charging. One is that your charging cable could be broken, try charging it with a different cable. Sometimes dirt can get inside the charging port or cable. Try cleaning the charging port and cable and then try plugging the device back in. Your battery could be completely depleted of energy and may not charge even when plugged in. In this case the battery needs to be replaced. There can also be water or dust damage within your device causing a short.