In order to find the correct options, we need to know the following property:
[tex]a^{\frac{b}{c}}=\sqrt[c]{a^b}[/tex]So, rewriting the expression 243^(3/5), we have:
[tex]243^{\frac{3}{5}}=\sqrt[5]{243^3}[/tex]That is, 243^(3/5) is the 5th root of 243 cubed. Its value is:
[tex]\sqrt[5]{243^3}=\sqrt[5]{14348907}=27[/tex]