Answer: 3. Never true
Step-by-step explanation
A radical number is of the form
![\sqrt[n]{x}](https://img.qammunity.org/2018/formulas/english/middle-school/zugjp9osfjifk0ex6hj3s0my1jfuakck.png)
where x s the radicand.
If x is of the form Mⁿ, where M is an integer, then the expression yields a rational number.
According to the question, the radicand is not a perfect power.
Therefore the expression cannot be a radical number.