## Social Question

#### Do you know why x is the unknown?

17 responses

It always seemed appropriate to me to take an infrequently used letter and use it to represent the unknown. The real reason, which I just learned today, is much more prosaic.

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thanks!

stanleybmanly (24128)

nice. My math mentor would have asked, ”y?

zenvelo (36881)

I actually though that I knew the answer to this question. It is that printing presses in medieval days had to use the extra x y and z’s for something so formulas had to use the extra letters. Sorry I didn’t read the link till now. My answer could still be right.

RedDeerGuy1 (19594)

“Extra” x, y, z’s @RedDeerGuy1?

Dutchess_III (44371)

@Dutchess_III Yes. The old fashioned printing presses used one letter at a time. X , y and z’s are not used as often.

RedDeerGuy1 (19594)

…..Well, it’s not like they’d go to waste or anything!

Dutchess_III (44371)

OK, now I’m trying to think…what kinds of things did they publish at the end of the medieval period, about 1400. Bibles would be #1, I would think. And there are no X’s (unknowns) in the Bible cuz the Bible knows everything. Just ask it.
Um….what else….this is a good question for Super Fluther! Thanks, @RedDeerGuy1! Wait…not it’s not. Too easy to Google.

Dutchess_III (44371)

Interesting! I thought it was for the same reason as you. I also figured x was a better choice than, say, l or o because those look like numbers. I’m guessing y and z are used as “secondary” unknowns because they’re close to x.

dxs (15160)

@RedDeerGuy1 , Feel free to hold onto your belief, but the use of x in algebra preceded the invention of the printing press by several hundred years. There are also some holes in your argument. You are assuming that all the letters in the alphabet were created in complete blocks. I don’t see why this would need to be the case. It would be rather wasteful, especially if punctuation marks were also included.

@dxs, I go along with what you say about use of y and z.

I’m guessing it’s simply that X marks the spot. It’s the easiest sign to make that seems to mean something, or can stand in for something. Didn’t illiterate people use the letter X to stand in for their signature?

Now I want to know who created algebra?! And why?

Dutchess_III (44371)

@RedDeerGuy1 Those extra y’s and z’s are brought over to Poland for them to use.

dxs (15160)

On a side note, I learned to cross my z‘s when I took second year algebra so as to not confuse it with a 2.

zenvelo (36881)

Well that explains that @zenvelo!

Dutchess_III (44371)

@zenvelo Don’t get me started. I’m sooo pedantic with my notation. So much that I invent my own notation.

dxs (15160)

Oy, I just filled out the paperwork to apply for citizenship for my MIL and kept writing z with a line across it, because it’s automatic for me. I tore up at least 3 pages and had to do them over. I didn’t trust the person processing the paper would be familiar with it.

I think X was a bad choice, because X for the first 5 or so grades means multiply. Then X becomes the unknown or an axis, and a dot now means multiply, or parenthesis means multiply, etcetera.

JLeslie (61642)

X means a LOT of things!

Dutchess_III (44371)

Yup.

JLeslie (61642)

or