If x+1/x=17/4, x>1, then what is the value of x-1/x ?

If x + \(\frac{1}{x}\)  = n

then 

then, x - \(\frac{1}{x}\)  = \(\sqrt {n^2 - 4}\)

If $x+\frac{1}{x}=\frac{17}{4}, x>1$

$x-\frac{1}{x}$ = \(\sqrt {(\frac{17}{4})^2 - 4}\)

$x-\frac{1}{x}$ = \(\sqrt {\frac{225}{16}}\) = \(\frac{15}{4}\)