Answer:
The additive inverse of 21i is -21i
Step-by-step explanation:
Let b be a real or complex number, the additive inverse of b is defined as a number x, such that:
[tex]b + x = 0[/tex]
So, if we clear x from the equation, we get:
[tex]x = -b[/tex]
Then the additive inverse of a number b is -b. In other words, the additive inverse of a number is the one that when you add it to the previous number the result is 0.
In this case we have a complex number.
Then:
[tex]b = 21i[/tex].
Where [tex]i = \sqrt{-1}[/tex]
So
[tex]21i + x = 0[/tex]
[tex]x = -21i[/tex].
The additive inverse of 21i is -21i
