若1/x+x=3,则x的平方除以（X的四次方加X的平方加1等于多少

x+1/x=3
两边平方
x^2+2*x*1/x+1/x^2=9
x^2+2+1/x^2=9
x^2+1/x^2=7
x^2/(x^4+x^2+1)
上下同除以x^2
=1/(x^2+1+1/x^2)
=1/(7+1)
=1/8