G^4+G^3+G^2+G+1
=G^4+G^3+2+(G^2+G-1)
=G^2(G^2+G)+2+(G^2+G-1)
=G^2(G^2+G-1+1)+2+(G^2+G-1)
=G^2(G^2+G-1)+(G^2+G-1)+G^2+2
=(G^2+G-1)(G^2+1)+G^2+2
=(G^2+G-1)(G^2+G-1-G+2)+G^2+2
=(G^2+G-1)(G^2+G-1)+(G^2+G-1)(2-G)+G^2+2
=(G^2+G-1)(G^2+G-1)+2G^2+2G-2-G^3-G^2+G+G^2+2
=(G^2+G-1)(G^2+G-1)+2G^2+3G-G3
=(G^2+G-1)(G^2+G-1)-G(G^2-2G-3)
∵G4+G3+G2+G+1=X^2
∴(G^2+G-1)(G^2+G-1)=X^2
G(G^2-2G-3)=0
X=G^2+G-1
G^2-2G-3=0
得证