I need help understanding how to get the nth root with an odd number

Question

This nth root problem is practice problem in my text book.  It shows number placement and such but I still can't get the answer that the text book has.  Please help.

n=21     584,539/258,295 - 1 = 1.0397

Answer 1

me dont understand the subjekt

but with numbers like that yu need kalkulater that hold 9 or more digits ("sientifik kalk")

1st root=1

2th root=square root or x^1/2

3rd root=kube root or x^1/3

nth root =x^1/n, n=1, 2, 3, 4, 5...

????????? 584539/258295 ???????? du that be konnekted tu roots sumhow ???

584539/258295=2.26306742290792, wotever that mite be

?????????? n=21... du yu want 21th root av sumthun ??????