[tex]\boxed{\begin{array}{l}\sf\sqrt[\sf5]{\sf81x} =\sqrt{3}\\\sf(\sqrt[\sf5]{\sf81x})^{10}=(\sqrt{3}) ^{10}\\\sf(81x)^2=3^5\\\sf6561x^2=243\\\sf x^2=\dfrac{243\div243}{6561\div243}\\\sf x^2=\dfrac{1}{27}\\\sf x=\dfrac{\sqrt{1}}{\sqrt{27}}\\\sf x=\dfrac{1}{3\sqrt{3}}\cdot\dfrac{\sqrt{3}}{\sqrt{3}} \\\sf x=\dfrac{\sqrt{3}}{3\cdot\sqrt{3^2}} \\\sf x=\dfrac{\sqrt{3}}{3\cdot3}\\\sf x=\dfrac{\sqrt{3}}{9}\end{array}}[/tex]
