Question 33539
{{{ ((36y^2-64x^2) / xy) / (6/x - 8/y) }}}
First ... look at the bottom of the complex fraction.  We need to go to common denominators.
{{{ ((36y^2-64x^2) / xy) / (6(y)/xy - 8(x)/xy) }}}
Add the fractions
{{{ ((36y^2-64x^2) / xy) / ((6y-8x)/xy) }}}
Since this is a Complex fraction ... and the denominators of both parts are the same ... they cancel.
{{{ (36y^2-64x^2) / (6y-8x) }}}
The numerator is a special product ( the difference of two squares )
{{{ (6y - 8x)(6y + 8x) / (6y-8x) }}}
Cancel the 6y-8x 
{{{ 6y + 8x }}}
Some instructors will accept this answer ... others will want you to continue.
{{{ 2(3y+4x) }}}