初三 数学 具体解答过程 请详细解答,谢谢! (12 21:1:43)

2x=√5-1
√5=2x+1
所以4x^2+4x+1=5
x^2=-x+1
x^4=(x^2)^2=x^2-2x+1=(-x+1)-2x+1=-3x+2

x^4+x^2+2x-1
=-3x+2+(-x+1)+2x-1
=-2x+2
=-(√5-1)+2
=3-√5

X=2分之根号5减1
2X+1=根号5
4X^2+4X+1=5
X^2=1-X
x4+x2+2x-1=X^2(X^2+1)+2X-1
=X^2(2-X）+2X-1=2X^2-X^3+2X-1
=2(X^2+1)-(X^3+1).....

x2(x2+1)+2x-1=x(x+2)(x2+1)-1
把X=……代入得出答案！～

x=（√5-1）/2
x4+x2+2x-1=x4+2x2+1-x2-1+2x-1=(x2+1)2-(x
+1)2-1=8-√5