Question

A polynomial function has -5√3i as a root. Which of the following must also be a root of the function?

-5-√3i
-5+√3i
5-√3i
5+√3i

Answer 1

Answer: is A

Explanation:

Answer 2

-5+√3i is the given root so -5-√3i must be the other root

Explanation:

We know that complex roots must come in pairs. The pairs are complex conjugates. (a+bi) and (a-bi)

You are missing a sign between -5 and the square root

So if - 5+ sqrt(3) i is a root, then -5 - sqrt(3) i must be a root

if -5 - sqrt(3)i is a root, then -5 + sqrt(3)i must be a root.

I will assume you missed a + sign

-5+√3i is the given root so -5-√3i must be the other root