Question

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

Answer 1

9i

Explanation:

Given a complex number `z=x+-yi` 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 `color(red)"sign"` of the imaginary term is reversed.

`rArr" For" -9i=0-9i`

Then `bar(z)=0+9i=9i`