Solution - Raising to a power

Step  1  :

 1.1     15 = 3•5

(15)¹ = (3•5)¹ = 3 • 5

Equation at the end of step  1  :

  ((140) +  (27)) +  (3•5)

Step  2  :

Equation at the end of step  2  :

  ((140) +  27) +  (3•5)

Step  3  :

Final result :

  144