Complex #'s Prac.

Let $\omega$ be a nonreal root of $z^3=1.$ Let $a_1, a_2,\dots,a_n$ be real numbers such that $\frac{1}{a_1 + \omega} + \frac{1}{a_2 + \omega} + \dots + \frac{1}{a_n + \omega} = 2 + 5i.$
Compute $\frac{2a_1 - 1}{a_1^2 - a_1 + 1} + \frac{2a_2 - 1}{a_2^2 - a_2 + 1} + \dots + \frac{2a_n - 1}{a_n^2 - a_n + 1}.$
 

Please I need help on this. It is very confusing.