Solution - Simplification or other simple results

Step  1  :

            1
 Simplify   —
            9

Equation at the end of step  1  :

   7         1
  —— • (0 -  —)
  15         9

Step  2  :

             7
 Simplify   ——
            15

Equation at the end of step  2  :

   7   -1
  —— • ——
  15   9 

Step  3  :

Final result :

   -7            
  ——— = -0.05185 
  135