Question

x^2-y^2/xy divided by 1/y - 1/x

Answer 1

i suggest using brackets in the future to make it clearer.

i'd first rewrite 1/y - 1/x as (x - y)/yx

then i'd rewrite x^2 - y^2 as (x - y)(y + x)

then i'd use the fact that a/b divided by c/d is simply a/b * d/c

and probably good to consider the case when |y| = |x|

Answer 2

It is (x+y). Check out tips on how to solve this type of problem on
http://www.oojih.com/show/algebra/exponentrationalradical/