If x^2 + 1x^2 = 38, then what is the value of ( x - 1/x )?

Answer: Option C

$$\begin{array}{rl}& x^2+\frac{1}{x^2}=38\\ & x^2+\frac{1}{x^2}-2=38-2\\ & {\left(x-\frac{1}{x}\right)}^2=36\\ & x-\frac{1}{x}=6\end{array}$$