Answer:
x = √√6, x = √√2
Step-by-step explanation:
x^8 - 8x^4 + 12
u^2 - 8u + 12
(u - 6)(u - 2)
(x^4 - 6)(x^4 - 2)
x^4 = 6 and x^4 = 2
x = √√6 x=√√2