Answer:
18-5i
B is correct.
Step-by-step explanation:
Given: [tex]18-\sqrt{-25}[/tex]
Simplify the given expression
Inside the square root negative number.
Using complex concept.
[tex]\sqrt{-1}=i[/tex]
[tex]\sqrt{-25}=\sqrt{25}\cdot\sqrt{-1}[/tex]
[tex]\sqrt{-25}=5i[/tex]
Substitute the value into original equation.
[tex]18-\sqrt{-25}\Rightarrow 18-5i[/tex]
Hence, The equivalent expression is 18-5i
