who was it the solved that equation please,

 

We don't know until you give us the context.

It was Pythagoras who described it for a right-angled triangle. Even though it is described as Pythagoras' Theorem it was in use by the Babylonians long before Pythagoras came along.

 

Are you talking about Fermat’s last theorem?

Bob

 

Not exactly, since that relationship for triangles was know to the ancient Greeks. What Pierre de Fermat did was to advance a conjecture, for which he claimed that he had a proof, that there were no integer solutions for n > 2.

From Wikipedia
In number theory, Fermat's Last Theorem (sometimes called Fermat's conjecture, especially in older texts) states that no three positive integers a, b, and c satisfy the equation a^n + b^n = c^n for any integer value of n greater than 2. The cases n = 1 and n = 2 have been known since antiquity to have infinitely many solutions.[1]

 

It was Pythagoras who described it for a right-angled triangle. Even though it is described as Pythagoras' Theorem it was in use by the Babylonians long before Pythagoras came along.

And quite possibly the Egyptians as well before even the Babylonians, though perhaps not quite as generally as the Babylonians did. They were particularly fond of the 3-4-5 right triangle.

 

Not exactly, since that relationship for triangles was know to the ancient Greeks. What Pierre de Fermat did was to advance a conjecture, for which he claimed that he had a proof, that there were no integer solutions for n > 2.

From Wikipedia
In number theory, Fermat's Last Theorem (sometimes called Fermat's conjecture, especially in older texts) states that no three positive integers a, b, and c satisfy the equation a^n + b^n = c^n for any integer value of n greater than 2. The cases n = 1 and n = 2 have been known since antiquity to have infinitely many solutions.[1]

If Fermat had an FPU, he wouldn't have worried so much about restricting his theorizing to integers and many hours of good quality math research effort could have been out towards more productive things. .

 

Thank you @BobTPH
Fermat's last theorem was the name could not remember

remembered pythagorous, which is the n = 2 part for a right angled triangle,