（x²-2x)²-2（x²-2x）-3=0

(x²-2x)²-2*(x²-2x)-3=0
x²-2x=t
t²-2t-3=0
D₁=k²-ac
D₁=(-1)²-1*(-3)=4
$T1,2 = \frac{-k+- \sqrt{D1} }{a}$
T1 = 1+2/1 = 3
T2= 1-2/1 = -1

x²-2x=3
x²-2x-3=0
D₁=k²-ac
D₁=(-1)²-1*(-3)=4
$X1,2 = \frac{-k+- \sqrt{D1} }{a}$
X1 = 1+2/1 = 3
X2= 1-2/1 = -1

x²-2x=-1
x²-2x+1=0
D₁=k²-ac
D₁=(-1)²-1*1 = 0 (1 корень)
$X3 = \frac{-k+- \sqrt{D1} }{a}$
X₃ = 1-0 / 1 = 1

Ответ: -1;1;3