In this complex number, assuming that the equation actually is 18- √-25, the real part is already simplified. However, the imaginary part can be simplified by taking out "i" from the root using the relation i = √-1. This is done below:
18 - √-25
18 - √(-1)(25)
18 - 5i
From the choices, the correct answer is 18 - 5i.
