Đáp án đúng: B Đặt z = x + yi. Khi đó ta có: $\begin{array}{l}x+yi+(2-i)(x-yi)=13-3i\Leftrightarrow 3x-y-(y+x)i=13-3i\\\Rightarrow \left\{ \begin{array}{l}3x-y=13\\x+y=3\end{array} \right.\Leftrightarrow \left\{ \begin{array}{l}x=4\\y=-1\end{array} \right.\end{array}$