Question

plz help me urgently

Answer 1

x-1/x=√5
(x-1/x)^3=x^3-1/x^3-3(x-1/x)
(√5)^3=x^3-1/x^3-3*√5
5√5=x^3-1/x^3-3√5
5√5+3√5=x^3-1/x^3
8√5=x^3-1/x^3