Answer:
[tex]4 \sqrt{2} \: i[/tex]
Step-by-step explanation:
[tex] \sqrt{ - 2} + \sqrt{ - 18} \\ ( \sqrt{2} \times \sqrt{ - 1} ) + ( \sqrt{18} \times \sqrt{ - 1} ) \\ ( \sqrt{2} \times \sqrt{ - 1} ) + (3 \sqrt{2} \times \sqrt{ - 1} ) \\ \sqrt{2} i + 3 \sqrt{2} i \\ = 4 \sqrt{2} i[/tex]