If x + 1/x = 3 , then find the value of x^3 + 1x^3 = ?

Answer: Option B

$$\begin{array}{rl}& x+\frac{1}{x}=\sqrt{3}\\ & \text{Cubing both side}\\ & \Rightarrow x^3+\frac{1}{x^3}+3.x.\frac{1}{x}\left(x+\frac{1}{x}\right)=3\sqrt{3}\\ & \Rightarrow x^3+\frac{1}{x^3}+3\left(\sqrt{3}\right)=3\sqrt{3}\\ & \Rightarrow x^3+\frac{1}{x^3}=3\sqrt{3}-3\sqrt{3}\\ & \Rightarrow x^3+\frac{1}{x^3}=0\end{array}$$