Question

Which of the following is equivalent to 18- √25?
5i
18 – 5i
18 + 5i
23

Answer 1

The answer is B

Explanation:

Answer 2

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.