Solution - Simplification or other simple results

Step  1  :

 1.1     15 = 3•5

(15)² = (3•5)² = 3² • 5²

Equation at the end of step  1  :

  (132) +  (32•52)

Step  2  :

Equation at the end of step  2  :

  132 +  (32•52)

Step  3  :

Final result :

  394