Question

Which of the following is not a real number?

Answer 1

`√(-3)`

Explanation:

Since each of these answers contain a radical, you want to find the one that has a negative value, because technically sqrt(some negative number) isn't defined, or rather it has no real solution. This is because you can rewrite a radical as
`√(a * b) = √(a) * √(b)`. And since
`i = √(-1)` you can rewrite
`√(-3)` as
`√(-1) * √(3)` which becomes
`i√(3)`