Answer:
[tex]3i \sqrt{7}[/tex]
Step-by-step explanation:
The imaginary unit is [tex]i=\sqrt{-1}[/tex].
Now 63 itself is not a perfect square but 63 does contain a factor that is.
63=9×7 and 9 is a perfect square.
So [tex]\sqrt{-63}=i \sqrt{63}[/tex].
[tex]i \sqrt{63}=i \sqrt{9 \cdot 7}=i \sqrt{9} \sqrt{7}=i(3) \sqrt{7}=3i \sqrt{7}[/tex]
