Question

Which of the following is equivalent to 18- the square root of -25? A. 5i B.18-5i C. 18+5i D.23 ?

Answer 1

remember
(√(mn))=(√m)(√n)
18-√(-25)
√(-25)=(√-1)(√25)=(√-1)(5)=5√-1
18-5√-1
remember that √-1=i
18-5i

B is the answer

Answer 2

The answer is B : the square root of 25 is 5, because 5x5=25. So it's 18-5.... Hope I helped :)