答：
x²-4x+1=0
两边同除以x得：
x-4+1/x=0
x+1/x=4
所以：
x²+x^(-2)
=x²+1/x²
=(x+1/x)²-2
=4²-2
=14
x^4+x^(-4)
=x^4+1/x^4
=(x²+1/x²)-2
=14²-2
=194