Hi there!
Answer:
D. 9i
*The answer must have a positive sign.*
Step-by-step explanation:
Lesson: Estimating and Comparing Square Roots.
Definition of Square Root
Square root- of a number is one of the number's two equal factors.
Every positive number has two square roots, one positive and one negative. The radical symbol, [tex]\sqrt{}[/tex], indicates the non-negative or principle square root.
First, you apply radical rule
[tex]\sqrt{-1}\sqrt{81}[/tex]
Then you apply imaginary by number rule.
[tex]\sqrt{81}i[/tex]
[tex]\sqrt{81}=9=9^2=9*9=81[/tex]
Therefore, the final answer is 9i.
I hope this helps you! :)
-Charlie
Thank you!
