Question

Let \( n \ge 2\) and \( k \ge 1 \) and let
\[
f(x) = \sum_{i=0}^{n-1} x^i
\]
Then \(f(x) \) divides \( f\left(x^{ k n} \right) -n\)

Answer 1

This is more general than the problem I posted before.