The answer is
[tex]a_{1} = - \sqrt[4]{54} \: \: \: \: \: a_{2} = \sqrt[4]{54} [/tex]
Solution:
[tex]a {}^{4}= 54 [/tex]
[tex]a {}^{4} = \frac{ + }{ } \sqrt[4]{54} [/tex]
[tex]a = - \sqrt[4]{54} [/tex]
[tex]a = \sqrt[4]{54} [/tex]
[tex]a_{1} = - \sqrt[4]{54} \: \: \: \: \: \: a _{2} = \sqrt[4]{54} [/tex]
