Respuesta :

Answer:

Step-by-step explanation:

[tex](x^4-81=0)\\(x^2-9)(x^2+9)=0\\(x-3)(x+3)(x^2+9)=0\\[/tex]

[tex]x = 3,\\x = -3\\x^2 + 9 = 0\\x^2 = -9\\x = \pm 3i[/tex]