x²+2x-1=0因为x≠0,等式两端同除以x得
x+2-1/x=0
(1)x-1/x=-2
(x-1/x)^2=4
x^2-2+1/x^2=4
(2)x^2+1/x^2=4+2=6
(x^2+1/x^2)^2=36
x^4+2+1/x^4=36
(3)x^4+1/x^4=34
x²+2x-1=0因为x≠0,等式两端同除以x得
x+2-1/x=0
(1)x-1/x=-2
(x-1/x)^2=4
x^2-2+1/x^2=4
(2)x^2+1/x^2=4+2=6
(x^2+1/x^2)^2=36
x^4+2+1/x^4=36
(3)x^4+1/x^4=34