Equations

Story of the x

In writings by Arab mathematicians prior to the 15^th century there are references to equations. They called the unknown element the thing, because they had  no other name for it.

“How much is the thing if when increased by five it is double the thing minus seven?”

The word thing in Arabic, is pronounced xay, so this is the expression  translators used. Later it was abbreviated to its initial letter, x.

Equations: degree and difficulty

Finding formulas to solve first and second-degree equiatons is not very difficult for mathematicians. Those problems were solved in the Middle Ages.

But this wasn´t the case with problems that had a higher degree than two. In fact, during the Renaissance, Italian mathematicians of the 16 ^th century, who were then considered the most advanced mathematicians, worked hard in this area.

At the end of the 17^th century they continued to find ways to solve equiations with a superior degree of up to four until, in the 19^th century, the Norwegian genius Niels Henrik Abel (1802-1829), demostrated that such formulas, in general, don´t exist.