Question

Which of the following is equivalent to ________?
5i
18 – 5i
18 + 5i
23

Answer 1

i=
`√(- 1)`

so 18-5i is your answer

Answer 2

18-5i

B is correct.

Explanation:

Given:
`18-√(-25)`

Simplify the given expression

Inside the square root negative number.

Using complex concept.

`√(-1)=i`

`√(-25)=√(25)\cdot√(-1)`

`√(-25)=5i`

Substitute the value into original equation.

`18-√(-25)\Rightarrow 18-5i`

Hence, The equivalent expression is 18-5i