ToRadicals

ToRadicals[expr] attempts to express all Root objects in expr in terms of radicals.

Examples

Convert roots to radicals:

ToRadicals[Root[#^2 - 2 &, 1]]
(* -Sqrt[2] *)

Solve and convert:

ToRadicals[Solve[x^3 - 2 == 0, x]]

Please visit the official Wolfram Language Reference for more details.