The author of this post made a mistake in their formula. Then they only added a correction below it, while not removing the mistaken one. Is there any reason to do so? Should I clean it up?

When I was in high school, they taught me to solve quadratic equations with this formula:

$$x=\frac{\sqrt{4 \text{ac}+b^2}-b}{2 a}$$

EDIT: The original formula is this one: $x = \dfrac{-b \pm\sqrt{b^2-4ac}}{2a}$, I confused it with another formula on Wikipedia.

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    $\begingroup$ I'd say yes, in addition its rather odd that \text[ac} was used $\endgroup$ Sep 15 at 12:04
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    $\begingroup$ I'd say no. The correct information is there, so what's the problem? $\endgroup$ Sep 15 at 12:31
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    $\begingroup$ Qualification of the yes: it would make the question more straightforward to read, there's no reason to keep a copy of the edit history in the post itself, and it fixes the typography error. That said none of these are big problems so I would not personally bother to edit. If you want to edit, I would say it is OK to do so. $\endgroup$ Sep 15 at 12:40
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    $\begingroup$ I'd say no as well, in the case where the original question has also received an answer; then cleaning up to delete the "edit" renders the initial answer(s) invalid. Referring to the question in question here, the question is old (asked nine years ago), so I see no reason for Ooker to intervene now. I prefer such meta questions on relatively recent posts. $\endgroup$
    – amWhy
    Sep 15 at 16:30

Questions on Math SE should read like questions, not breaking news reports which are being continually updated. If an error has been corrected by an edit, but the original mistake is still included, then anyone should feel free to remove the error and replace it with the corrected text unless the original error is somehow fundamentally important to the asker's underlying question.

Any time you see a post with the text "EDIT: [some update which was added later]", it is reasonable to edit the post in order to incorporate that edit into the main body of the question (again, unless the fact that the text is an edit is fundamental to the question itself).

The entire edit history of a post is accessible for anyone who is interested in how the sausage is made.

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    $\begingroup$ I agree, with the exception in cases where an OP incorporates and EDIT: which fundamentally changes a question which has already been answered by answerers. In such cases, every such edit makes the question a moving target. Mind you, I'm referring only to edits by OP's that change a question already answered. $\endgroup$
    – amWhy
    Sep 15 at 16:28
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    $\begingroup$ Also, this question is about a question posted 9 years ago. Absolutely no need to edit and bump the post! $\endgroup$
    – amWhy
    Sep 15 at 16:34
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    $\begingroup$ @amWhy I'm not sure why an old question needs no edit and to be bumped? The spirit of the SE network as I know is that every question is subjected to updated to the best $\endgroup$
    – Ooker
    Sep 15 at 17:16
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    $\begingroup$ Not necessarily, when weighed against other factors. For example, three answers exist, to that question. The OP was considerate enough to respect answers to their initial post, adding "edit: ...................... " to clearly demonstrate the sequence of events, and not to render the initial answer(s) meaninless. And you want to come in 9 years later and erase that effort, possibly rendering one or more answers unexplainable? No, don't do that. My advice to you would be that you focus on more recent questions/answers/comments. $\endgroup$
    – amWhy
    Sep 15 at 17:22
  • $\begingroup$ @amWhy Regarding your first comment: my suggestion in that case would be to roll back the edit, and encourage the asker to post a new question (but I think that it can also be argued that an edit which changes the meaning of a question is fundamental to the question itself). $\endgroup$
    – Xander Henderson Mod
    Sep 15 at 19:19
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    $\begingroup$ "roll back the edit, and encourage the asker to post a new question...." If the asker hasn't been here in six years, that's going to take an awful lot of encouragement. $\endgroup$ Sep 16 at 5:53
  • $\begingroup$ I think one needs to be very careful, since there might be answers which only make sense if the edit is not removed $\endgroup$
    – Filippo
    Sep 29 at 6:14

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