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Câu hỏi: Cho hai số phức $z$ thỏa mãn $\left( 2+i \right)z+4i=\left( 3-i \right)z+5$. Tìm $\bar{z}$.
A. $\bar{z}=-\dfrac{13}{5}+\dfrac{6}{5}i$.
B. $\bar{z}=\dfrac{13}{5}-\dfrac{6}{5}i$.
C. $\bar{z}=-\dfrac{13}{5}-\dfrac{6}{5}i$.
D. $\bar{z}=\dfrac{13}{5}+\dfrac{6}{5}i$.
A. $\bar{z}=-\dfrac{13}{5}+\dfrac{6}{5}i$.
B. $\bar{z}=\dfrac{13}{5}-\dfrac{6}{5}i$.
C. $\bar{z}=-\dfrac{13}{5}-\dfrac{6}{5}i$.
D. $\bar{z}=\dfrac{13}{5}+\dfrac{6}{5}i$.
$\left( 2+i \right)z+4i=\left( 3-i \right)z+5\Leftrightarrow \left( -1+2i \right)z=5-4i\Leftrightarrow z=\dfrac{5-4i}{-1+2i}=-\dfrac{13}{5}-\dfrac{6}{5}i$
Suy ra $\bar{z}=-\dfrac{13}{5}+\dfrac{6}{5}i$
Suy ra $\bar{z}=-\dfrac{13}{5}+\dfrac{6}{5}i$
Đáp án A.