Solution - Simplification or other simple results

Step  1  :

Equation at the end of step  1  :

  ((3•7x213) • x) -  20
 Step  2  :

Trying to factor as a Difference of Squares :

 2.1      Factoring:  21x²¹⁴-20 

Theory : A difference of two perfect squares,  A² - B²  can be factored into  (A+B) • (A-B)

Proof :  (A+B) • (A-B) =
         A² - AB + BA - B² =
         A² - AB + AB - B² =
         A² - B²

Note :  AB = BA is the commutative property of multiplication.

Note :  - AB + AB equals zero and is therefore eliminated from the expression.

Check :  21  is not a square !!

Ruling : Binomial can not be factored as the
difference of two perfect squares

Final result :

  21x214 - 20