Question

Giải giúp e câu 4 5 6 với ạ

Answer 1

​đặt Z=a+bi

​bài 4: \(\left\{{}\begin{matrix}a=2\sqrt{3}\\r=\sqrt{a^2+b^2}=4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=2\sqrt{3}\\b=\pm2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}Z=2\sqrt{3+2i}\\Z=2\sqrt{3}-2i\end{matrix}\right.\)

​bài 5:tương tự \(\left\{{}\begin{matrix}b=6\\a=\pm8\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}Z=8+6i\\Z=-8+6i\end{matrix}\right.\)

bai 6: Z= a+bi \(\Rightarrow\)\(\overline{Z}=a-bi\)

bài ra \(\Rightarrow\left\{{}\begin{matrix}a=-12\\a-3b+4=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=-12\\b=\dfrac{-8}{3}\end{matrix}\right.\)

vay Z= -12-\(\dfrac{8}{3}i\)