If $\frac{8x}{2x^2 + 7x - 2} = 1, x > 0$, then what is the value of $x^3 + \frac{1}{x^3}$?

$\frac{5}{4}\sqrt{17}$ $\frac{5}{8}\sqrt{17}$ $\frac{3}{4}\sqrt{17}$ $\frac{3}{8}\sqrt{17}$

$\frac{5}{8}\sqrt{17}$