Answers: 0.08 and -0.08; 0.09i and -0.09i.
When taking square roots, we take the positive and negative answers. This gives us the first answer.
For the second answer, we rewrite -0.0081 as a complex number:
[tex]\sqrt{-0.0081}=\sqrt{0.0081i^2}=i\sqrt{0.0081}=\pm0.09i[/tex]