# How do you write the complex conjugate of the complex number -9i?

Sep 18, 2016

9i

#### Explanation:

Given a complex number $z = x \pm y i$ then the complex conjugate is.

color(red)(bar(ul(|color(white)(a/a)color(black)(bar(z)=x∓yi)color(white)(a/a)|)))

Note that the real term remains unchanged while the $\textcolor{red}{\text{sign}}$ of the imaginary term is reversed.

$\Rightarrow \text{ For} - 9 i = 0 - 9 i$

Then $\overline{z} = 0 + 9 i = 9 i$