Solution - Simplification or other simple results

Step  1  :

 1.1     21 = 3•7

(21)² = (3•7)² = 3² • 7²

Equation at the end of step  1  :

  80    
  —— -  (2 • (32•72))
  4     

Step  2  :

Equation at the end of step  2  :

  80    
  —— -  (2•32•72)
  4     

Step  3  :

            20
 Simplify   ——
            1 

Equation at the end of step  3  :

  20 -  (2•32•72)

Step  4  :

Final result :

  -862