Question

What is the complex conjugate of `20i`?

Answer 1

`color(green)(-20i)`

Explanation:

The complex conjugate of `color(red)a+color(blue)bi` is `color(red)a-color(blue)bi`

`color(blue)(20)i` is the same as `color(red)0+color(blue)(20)i`
and therefore it's complex conjugate is `color(red)0-color(blue)(20)i`
(or just `-color(blue)(20)i`)