If 21x = 79x, what is the value of x?

I am first found in caves, now prolific online; I am a depiction, a drawing, a symbol, or sign. I will convey whichever mood you could wish; or for that matter, a fist, flask, or fish. What am I?

You walk into an old horror house. It has no power or plumbing. Once inside, you see three doors. Each door has a number on it. Behind each door is a way for you to die. Behind door number one, you die by getting eaten by a lion. Behind door number two, you die by getting murdered. Behind door number three, you die by an electric chair. You can’t turn back, so you have to go through a door. Which door do you go through?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

How many bricks does it take to complete a building that is 15 feet wide, 30 feet deep, and 12 feet tall made of brick?

We can be boring,Or interesting.
We can be long,Or short.
We can have pictures,Or just words.
Many love us,But many also hate us.
What are we?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

Find out the missing number in the picture attached:

A guy in his thirties is found dead in a forest. The shocking thing about the body is that he is wearing his swimming trunks snorkel and a facemask.

For your information, the nearest lake is some 10 miles away and the sea is hundreds of miles away.

How did he die then?

Known by all without exception, Forever here, for your protection, Sometimes strong, sometimes weak, Right after the night I come - hot and chic. And while millions of miles away, I always get to you, I find my way. No life around could do without me, Can you guess what I might be?