mmb1

Verified answer

(x^2+2x)^2-2(x+1)^2=1
(x^2+2x)^2-2(x^2+2x+1)=1
x^2+2x=t
t^2-2(t+1)=1
t^2-2t-2=1
t^2-2t-3=0
t12=(2+-корень(2+12))/2=(2+-4)/2=3 -1
x^2+2x=3
x^2+2x-3=0
x12=(-2+-корень(4+12))/2=(-2+-4)/2=-3 1
x^2+2x=-1
x^2+2x+1=0
(x+1)^2=0
x3=-1