x²-2x-1=0
x-2-1/x=0
x-1/x=2
(x-1/x)²=4
x²+1/x²-2=4
x²+1/x²=6
x²/(x^4+x²+1)
=1/(x²+1+1/x²)
=1/(6+1)
=1/7