Why is unknown value in Maths always taken as 'X'

 Admit it or not, almost all of us have asked this question at some point in our life, maybe in our mathematics classes!

Well, today I am here to solve the mystery of the letter ‘X’.

You might have noticed, now this letter ‘X’ is not only confined to the field of mathematics but it’s almost everywhere, it will be quite correct to say that it has become a part of our colloquial language, isn’t it?

Anyway, the origin of this mysterious letter dates back to those eras when western scholars began to explore Arabic mathematics.

Now among the many brilliant inventions and discoveries, Arabs are also credited for the study of Al-jabr or Algebra.

The Arabic texts containing these brilliant records were finally brought to the European countries, mainly Spain in the 11th and 12th century by the European scholars and when they arrived, there was a massive interest which demanded a translation of this mathematical wisdom from Arabic into European languages.

But there were many problems encountered, one problem being that the Europeans faced a lot of difficulties in pronouncing some sounds in Arabic.

Also, these sounds tend not to be represented by the characters available in the European languages.

For example, take this letter sheen.

It makes the sound — sh.

Also, it is the first letter of the Arabic word ‘Shayun’ which means something. Just something means some undefined, unknown thing. In Arabic ‘—al’ is added to a word to make it definite.

Now, if we add ‘al’ to ‘shayun’, it becomes Al-shayun or ‘the unknown thing’.

And this was the word that appeared almost everywhere in the Arabic works of mathematics.

Now, the problem faced by the Spanish scholars while translating these texts was with this letter ‘sh’ or ‘shayun’ because Spanish doesn’t have that ‘sh’ sound.

So, they created a rule and borrowed the ‘ck’ sound from the classical Greek, which is represented by the greek letter chi. Here’s what chi looks like

Second theory

The second theory states that when Descartes was writing his Discours, he used a, b, c for known values and x, y, and z for unknowns. Unfortunately the typesetter ran out of y and z, and so the book finished up specialising in x as ‘the unknown quantity’. Descartes’ plan was to rotate the three ‘unknowns’ evenly.

So which theory do you believe tell me in the comment section😁.