Question

What's wrong with this "proof?"

Does there exist \(x\) such that \(x^2-5x+6=0\)?

Solution: \(x^2-5x+6=0 \\ (x-2)(x-3)=0 \\ x=2~\text{ or }~3~~~\blacksquare\)

Answer 1

If I heard correctly, it's because I assumed there is value at beginning, hence assumed hypothesis is true. but I don't understand the problem with it...?

Answer 2

Does anyone have idea?

Answer 3

it looks alright to me

Answer 4

Well, it is acceptable to normal person, but this proof is not exactly appropriate in "mathematical proof" world.

I just don't really understand why...

Answer 5

@satellite73 @abb0t @Hero
Have any idea?