Respuesta :

kcnawlay170

Answer:

x^4 - 81 = 0  

(x² - 9)(x² + 9) = 0  

Notice that the first of these is itself a difference of two squares:  

(x - 3)(x + 3)(x² + 9) = 0  

So the solutions are x = 3, x = -3, x = 3i, x = -3i