We are given the following radical
[tex]\sqrt[]{243}[/tex]Let us reduce the above radical
We need to break the number 243 into a product of factors
Notice that 81 and 3 are the factors (83×3 = 243)
[tex]\sqrt[]{243}=\sqrt[]{81}\cdot\sqrt[]{3}[/tex]Since 81 is a perfect square so the radical becomes
[tex]\sqrt[]{243}=\sqrt[]{81}\cdot\sqrt[]{3}=9\cdot\sqrt[]{3}[/tex]Therefore, the simplified radical is
[tex]undefined[/tex]