summation - What is the sum of the series $x^{n-1} + 2x^{n-2} + 3x^{n-3} + 4x^{n-4} + cdots + nx^{n-n}$?

$x^{n-1} + 2x^{n-2} + 3x^{n-3} + 4x^{n-4} + \cdots + nx^{n-n}$

I'm not sure if this can even be summed. Any help is appreciated.