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Let $$S = \{z \in \mathbb{C} : \bar{z}^2 + \bar{z} = 0\}$$. Then $$\sum_{z \in S} (\text{Re}(z) + \text{Im}(z))$$ is equal to______.
Correct Answer: -1
Given,
$$S=\{z\in\mathbb C:\bar z^2+\bar z=0\}$$
We have
$$\bar z^2+\bar z=0$$
$$\bar z(\bar z+1)=0$$
Hence,
$$\bar z=0\quad \text{or}\quad \bar z=-1$$
Taking conjugate on both sides,
$$z=0\quad \text{or}\quad z=-1$$
Thus,
$$S=\{0,-1\}$$
Now compute
$$\sum_{z\in S}(\operatorname{Re}(z)+\operatorname{Im}(z))$$
For
$$z=0,$$
$$\operatorname{Re}(0)+\operatorname{Im}(0)=0$$
For
$$z=-1,$$
$$\operatorname{Re}(-1)+\operatorname{Im}(-1)=-1+0=-1$$
Therefore,
$$0+(-1)=-1$$
Hence, the required value is
$$\boxed{-1}$$.
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