Fermat's Last Theorem is easily demonstrated using the binomial theorem - simple algebra. It is dismissed as a proof because most fail to "see" or "understand" variables - particularly mathematicians. Fermat gave us a hint as to his "demonstration" by where he wrote his comment ( https://en.wikipedia.org/wiki/Diophantus_II.VIII ). The difference of two squares can - in some cases - be a square - Pythagorean triples! The difference (or sum) of two integers raised to a power greater than two - nope.