x2-5x+1=0
x^2/x-5x/x+1/x=0
x+1/x=5
x^2+1/x^2
=(x+1/x)^2-2
=5^2-2
=23
x^4+1/x^4
=(x^2+1/x^2)^2-2
=23^2-2
=527