week 3 pre calculus 11 – negative sign in root sign

This week I learned that if a numbers index is even like 2, there cant be a negative sign in the root because negatives dont have an even root so it makes it impossible, but if the index is odd like 3, you can still put the negative sign in the root.

examples: is impossible because the index is 2 which is even (it is invisible).

is possible because the index is 3 which is odd.