Use factor theorem to verify that `x+a` is a factor of `x^n+a^n` for any odd positive integer.

Explanation

Let `f(x)=x^n+a^n`
Putting `x = −a` in `f(x)`, we get:
`f(−a)=(−a)^n+a^n`
If `n` is any odd positive integer, then
`f(−a)=(−a)^n+a^n`
`=>f(-a)=−a^n+a^n=0`
`therefore` By factor theorem, `(x + a)` is a factor of `(x^n+a^n)` for any odd positive integer.