Answer:
x = -5, 5, -5i, 5i.
Step-by-step explanation:
Solving
x^4 - 625 = 0. The square root of 625 is 25 so we have:
(x^2 - 25)(x^2 + 25) = 0
(x - 5)(x + 5) (x^2 + 25) = 0
