[tex] a = \sqrt [4]{\dfrac{ \it 1}{ \it 162}} = \dfrac{\sqrt[4]{\it1}}{\sqrt[4]{\it162}} =\dfrac{\it1}{\sqrt[4]{\it162}}
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\sqrt[4]{\it162} =\sqrt[4]{ \it 3^4\cdot2} = 3\sqrt[4]{\it 2} = 3\sqrt[4]{\it \dfrac{16}{8}} = 3\cdot 2 \cdot \dfrac{1}{\sqrt[4]{8}} = \dfrac{6}{ \sqrt[4]{8}} [/tex]
[tex]\it a = \dfrac{1}{\dfrac{6}{ \sqrt[4]{\it8}}} = \dfrac{\sqrt[4]{\it8}}{ \it6}[/tex]
