Write the 's as  so everything
will be fractions:



Put parentheses around the top and bottom:



The LCD of all four denominators is .
Put it over 1 and put parentheses around it, 
Then multiply top and bottom by that:

 

Now use the distributive principle to remove the 
parentheses on the right:



Cancel the 's in the top left and the bottom right
terms and erase the 's and we get



Remove the parentheses and we get:



Combining terms on top and bottom, we end up with



Edwin