Respuesta :

The roots can be found as,

[tex]\begin{gathered} x^4-81=0 \\ (x^2+9)(x^2-9)=0 \\ (x^2+9)(x+3)(x-3)=0 \\ x=\pm3i,3\&-3 \end{gathered}[/tex]

Thus, the roots of the equations are 3i,-3i,3 and -3.