Question 627200
Reduce each fraction to lowest term.
<pre>
abx - 2aby
覧覧覧覧覧 = 
  2y - x

Factor out ab in the numerator:

ab(x - 2y)
覧覧覧覧覧 = 
  2y - x

Notice that the x - 2y in the top and the 2y -x in the bottom are
similar but not the same.  Here is what we do with the 2y - x to the side:

                                      2y - x
                Reverse the terms    -x + 2y
                Rewrite -x as -1x   -1x + 2y
                Factor out -1      -1(x - 2y)
Substitute that for the denominator:

 ab(x - 2y)
覧覧覧覧覧覧 = 
 -1(x - 2y)

Now cancel the (x - 3y)'s

 ab<s>(x - 2y)</s>
覧覧覧覧覧覧 = 
 -1<s>(x - 2y)</s>

All that's left is

 ab
覧覧  
 -1   

which equals

-ab

Edwin</pre>