Answer:
x = 8 or x = -8
Step-by-step explanation:
x^4 - 256 = 0
<=>x^4 - 4^4 = 0
<=>(x - 8)(x + 8)(x^2 + 64) = 0
Case 1 :
x - 8 = 0
<=>x = 8 (choose)
Case 2:
x + 8 = 0
<=>x = -8 (choose)
Case 3:
x^2 + 64 = 0
<=>x^2 = -64 (nonsense)
so x = 8 or x = -8
Done :))
