so remember that
\(\sqrt{x} \sqrt{y} = \sqrt{xy}\) so
\(\sqrt{-18} = \sqrt{9} \sqrt{-1} \sqrt{2} =3i\sqrt{2}\)
\(\sqrt{-2} = \sqrt{-1} \sqrt{2} =i\sqrt{2}\)
\(i\sqrt{2}+3i\sqrt{2}=\sqrt{2}(i+3i)=\sqrt{2}(4i)=4i\sqrt{2}\)
answer is second one or \(4\sqrt{2}i\)
