Question 6138
first clear your parentheses, by raising everything to the power indicated:

{{{(x/y)^3 / (x/2y)^3}}}
{{{(x^3/y^3)/(x^3/8y^3)}}}

with complex fractions, you just flip the bottom turn and multiply:
{{{(x^3/y^3)*(8y^3/x^3)}}}
{{{8x^3y^3/x^3y^3}}}
the x^3 and y^3 terms reduce to 1, so the answer is 8