Solution - Simplification or other simple results

Reformatting the input :

Changes made to your input should not affect the solution:

 (1): "f2"   was replaced by   "f^2". 

Step  1  :

            21
 Simplify   ——
            25

Equation at the end of step  1  :

               21
  ((f2) • d) • ——
               25

Step  2  :

Final result :

  21f2d
  —————
   25