Question

(x^2+1)^2-8(x^2+1)-20=0

Answer 1

2X^2+2-8X^2-8-20 = 0
2X^2-8X^2 = 20 + 8 - 2 
-6X^2 = 26
X^2 = 4
X = 2

Answer 2

вот надеюсь правельно