Question

If 1,a₁,a₂,a₃...,a_n-1 are the nth roots of unity, prove that:

^{\(\frac{1}{2-a_1}+\frac{1}{2-a_2}+...+\frac{1}{2-a_{n-1}}=\frac{(n-2)2^{n-1}+1}{2^n-1}\)}