Giải:
Đặt \(z=a+bi(a,b\in\mathbb{R})\)
Theo bài ra ta có: \(z-(2+3i)\overline{z}=1-9i\)
\(\Leftrightarrow (a+bi)-(2+3i)(a-bi)=1-9i\)
\(\Leftrightarrow -(a+3b)+3i(b-a)=1-9i\)
\(\left\{\begin{matrix} a+3b=-1\\ b-a=-3\end{matrix}\right.\Rightarrow \left\{\begin{matrix} a=2\\ b=-1\end{matrix}\right.\Rightarrow z=2-i\)