Answer:
Solving the radical [tex]\pm\sqrt{-81}[/tex] we get [tex]\mathbf{\pm9 \ i}[/tex]
Step-by-step explanation:
We need to express the radical [tex]\pm\sqrt{-81}[/tex] using the imaginary unit i
Prime factors of 81 are: 3x3x3x3
and [tex]\sqrt{-1}=i[/tex]
Solving:
[tex]\pm\sqrt{-81}\\=\pm\sqrt{81}\sqrt{-1}\\=\pm\sqrt{3\times3\times3\times3}i\\ =\pm\sqrt{3^2\times3^2}i\\=\pm3\times3\ i\\=\pm9 \ i[/tex]
So, Solving the radical [tex]\pm\sqrt{-81}[/tex] we get [tex]\mathbf{\pm9 \ i}[/tex]
