Why mathimatica cant solve it ??
Reduce[16 == y^y^y, {y}] Solve[16 == y^y^y, {y}] FindInstance[16 == y^y^y, {y}] WolframAlpha["16=y^y^y"]
For trascendental equation it is advisable to give a bound for the variable:
Reduce[16 == y^y^y && Abs[y] < 4, y, Reals] Reduce[16 == y^y^y && Abs[y - 2] < 1, y]
Hey Ismail, Try using the link http://m.wolframalpha.com/input/?i=16%3Dy%5E%28y%5Ey%29
You will find