2(x²+2+1/x²)-9(x+1/x)+10=0
2(x+1/x)²-9(x+1/x)+10=0
(2x+2/x-5)(x+1/x-2)=0
2x+2/x-5=0 x+1/x-2=0
∴x=2 x=1/2 x=1