In 1830, Évariste Galois proved that most equations of degree higher than four cannot be solved by radicals, and showed that for each equation, one may decide whether it is solvable by radicals, and, if it is, solve it.
Dǎɣ 1830, Évariste Galois asikna as iyadak dǎɣ alɣisaban ən degré ogaran ikoz waradoben adiqil ayknan fal radiəautan, əd isikna as hak alɣisab, nadobat ananu as taqal aylayaman fal radikotan, əd, afal taqal, ye kanan.