> I can’t stand using a hyphen to mean negative or subtract
I wonder what the difference is. Maybe in unicode one is slightly longer than the other, but at the end of the day, aren't they both just a horizontal line?
The first one is correct. It contains the Unicode character 'MINUS SIGN' (U+2212). The second contains the Unicode character 'HYPHEN-MINUS' (U+002D) which is not suitable for representing the minus sign in mathematical typesetting.
Also, see https://i.imgur.com/ngFI3JB.png for a few examples typeset with MathJax. The first example has a proper minus sign (correct) whereas the second one contains a hyphen (incorrect). By the way, in plain HTML, the character entity reference "−" displays the minus sign, although I just use MathJax when proper mathematics typesetting is required in HTML pages.
In proportional fonts, the minus sign is significantly longer and usually slightly higher and thinner than the hyphen (so it lines up with the horizontal bar of the + sign). If you’re used to it, it looks much better than a hyphen. (Similar to using real quotation marks instead of the straight ones etc.)
A properly rendered minus is identical to the horizontal stroke of a plus (whereas hyphen is frequently shorter and/or incorrectly vertically aligned).
I wonder what the difference is. Maybe in unicode one is slightly longer than the other, but at the end of the day, aren't they both just a horizontal line?