Školjka

%V0 Za $a \in \mathbb{R}$ riješite sustav jednadžbi $$$\begin{align*} &x_{1}^{2} + ax_{1} + \left( \frac{a-1}{2} \right)^{2} = x_{2}\\ &x_{2}^{2} + ax_{2} + \left( \frac{a-1}{2} \right)^{2} = x_{3}\\ &\vdots\\ &x_{n-1}^{2} + ax_{n-1} + \left( \frac{a-1}{2} \right)^{2} = x_{n}\\ &x_{n}^{2} + ax_{n} + \left( \frac{a-1}{2} \right)^{2} = x_{1}. \end{align*}$$$