Respuesta :

With the denominators being either 3 or 4, the LCD is 3(4) = 12.

Right away, mult. all 4 terms of x/4-y/3 over x/3+y/4 by the LCD (12). 

We get:  3x - 4y
             ------------  which is already in the simplest form possible.
               4x + 3y