急 x平方减x加1分之x=7,求 x的4次方加X方加1分之x平方 的值.

x/(x^2-x+1)=7,
(x^2-x+1)/x=1/7
x+(1/x)-1=1/7
x+(1/x)=8/7
x^2/(x^4+x^2+1)
=1/[(x^4+x^2+1)/x^2]
=1/[x^2+(1/x^2)+1]
=1/[(x+(1/x))^2-2+1]
=1/[(x+(1/x))^2-1]
=1/[(8/7)^2-1]
=49/15