Origin of the variable X in Algebra

I am the product of STEM field, therefore Mathematics are part of my life. I always wondered why are we using the letter X to describe an unknown variable.
Algebra was originally founded by the Persian mathematician Al-Khwarizmi, sure its roots traces back to the ancient Babylonians but the Persian genius established algebra as a mathematical discipline that is independent of geometry and arithmetic in his book "The Compendious Book on Calculation by Completion and Balancing".

Thus my unanswered question keeps popping up, How did " الشيء =  the unknown thing" became X 😐?

I discovered that we're clueless on the subject. The unknown variable's origin is unknown. How cool is that!
Many speculated all sorts of hypothesis, from sexy to logical and boring. Regardless of what we wish to be true, science doesn't care about our feelings.

The sexy hypothesis:

 One Terry Moore hypothesized that while translating the Arabic works by the Spanish, the people who were tasked with this historical burden couldn't find any letter in the alphabet to replace the "ش=ch" in الشيء since Hispanics can't pronounce it. Which is a cool fact about the Arabic language, On the contrary to what western media, comedians and uninformed individuals allegedly claim about the language. It's a language of poetry that will take your tongue places :p it's written from write to left and letters are connected to each other, which sat a whole artistic era around cool writings and styles. There are some great works in poetry from even before Islam and it's really a wonderful thing to be exposed to a whole different world.  

Anyway back to the topic, i drifted a bit. Being an Arab in the 21st century makes you drift sometimes :p 

So the Spanish people borrowed the Greek letter chi which is written like an X and then it became by convention and through practice the common X we all know today.

Moral of the story: 
We've been in search for the X our whole academic lives because Hispanics can't speak Arabic. 
Haha, see that's a cool story, but as i said science doesn't care about being badass and this hypothesis lacks any real evidence and has many flaws concerning dates of translation that doesn't quite match.

The boring hypothesis:

Which is more logical and dull than the late one.
The use of x (as well as y and z) became common thanks to René Descartes' use of the last three letters of the alphabet to represent unknown quantities in his treatise La Géométrie. 
Since they were the least used letters in the alphabet and i can confirm that since I've been studying french from the age of Eight. Descartes found it a good idea and following that logic used the letters a,b and c for constants. 

Moral of the story:
Descartes was a lazy person, even though he created history, made god like achievements and will be remembered till our extinction. Certainly ironic, LOL.



I am not going through the usual talk of "proud of being an Arab". It resonates as nonsense to me. They were good man and did marvelous things for humanity and for their century. I aspire to be as committed as they were to everything i do. 

One last thing about the Arabs and the Arabic language: 

Learn the language, read history, speak to locals and formulate your own opinion. These people are warm and humble. Certainly being born in Tunisia, made me have a real sympathy for all sorts of cultures around the globe. I take nothing for granted and collect as much information as i could before spitting nonsense out of my mouth.

I heard an American comedian make a joke about how the Arabic language sounds dangerous. I know it's a joke and he's a great dude but it kinda triggered me that regardless of his intentions, in reality most people think so.

Plus, I've had enough of movies where the Arabian dude only says Allah and some nonsense that isn't Arabic at all in a demonic accent.  It's not like we have five words in our dictionary. 
I am not defending anyone here, but witnessing such a poetic language being thrown to the garbage of history brings me sadness.


In my opinion, like Latin, Arabic is going places but not the future. That is the fate of everything in this universe, so it comes as no surprise to me.
Nevertheless, I am so grateful for acquiring such an exquisite taste. I am not playing any victim-hood game and speaking of how unfortunate to be born in a third world country. 
From ashes emerges beautiful things, and oh boy we've had it rough compared to people from different corners of the world. Ignorance, famine, poverty, being slaves of the 21st century. 
I wouldn't have it any other way, i like the person i am today and i accept the cruelty of the world. 
Finding beauty in the mud became a hobby of mine.