Answer:
7i.
Step-by-step explanation:
Note : The given expression must be [tex]\sqrt{-49}[/tex].
We have to write this radical value in the imaginary value.
The given value can be rewritten as
[tex]\sqrt{-49}=\sqrt{49\times (-1)}[/tex]
[tex]\sqrt{-49}=\sqrt{49}\times \sqrt{-1}[/tex] [tex][\because \sqrt{ab}=\sqrt{a}\sqrt{b}][/tex]
[tex]\sqrt{-49}=7\times i[/tex] [tex][\because \sqrt{-1}=i][/tex]
[tex]\sqrt{-49}=7i[/tex]
Therefore, the required expression is 7i.