What does this rebus mean?

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Replace The Question Mark Below With the Correct Number.

2 {38} 3
4 {1524} 5
6 {3548} 7
8 {????} 9

I am something people love or hate. I change peoples appearances and thoughts. If a person takes care of them self I will go up even higher. To some people I will fool them. To others I am a mystery. Some people might want to try and hide me but I will show. No matter how hard people try I will Never go down. What am I?

Sherlock Holmes was challenged to make a pre-drawn line smaller without erasing it. He did it in fractions of seconds. How?

What always comes into a house through the keyhole?

In this image, you can see three almost identical Doraemon images. Can you spot the odd one out from them?

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

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Find the missing letter in the last circle logically in the given below picture.

A man is found dead in his bathroom naked with blood scattered all around him. The bathroom was locked from the inside and there is no trace of any struggle. There is nothing in the bathroom except his pant with the belt still around and his shirt. Also, the medic team can't find any incision in his body that may have been the reason behind so much blood loss.

The Police department is clueless regarding this murder mystery.
Can you?