Hi Katiee,
If c is a negative number than there will be answers that are real numbers only if n is odd.
Lets look at a couple examples
if
x2 = -4
then there are no solutions that are real numbers (what number squared equals -4?)
on the other hand if we have
x3 = -8
then we do have solutions with real numbers
-23 = -8 and therefore x = -2 is a real solution.
Hope this helps