Question

Please explain it to me first one so I can do other ones by myself

Answer 1

Note that if a + bi is a root of P(x) = 0, then a – bi is also a root of P(x) = 0.

18.

Given root:

`\begin{gathered} 1+4i \\ \sqrt[]{3} \end{gathered}`

Additional roots:

`\begin{gathered} 1-4i \\ -\sqrt[]{3} \end{gathered}`