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Solution - Simplification or other simple results

x320
x^3-20

Step by Step Solution

Step  1  :

Trying to factor as a Difference of Cubes:

 1.1      Factoring:  x3-20 

Theory : A difference of two perfect cubes,  a3 - b3 can be factored into
              (a-b) • (a2 +ab +b2)

Proof :  (a-b)•(a2+ab+b2) =
            a3+a2b+ab2-ba2-b2a-b3 =
            a3+(a2b-ba2)+(ab2-b2a)-b3 =
            a3+0+0-b3 =
            a3-b3


Check :  20  is not a cube !!
Ruling : Binomial can not be factored as the difference of two perfect cubes

Polynomial Roots Calculator :

 1.2    Find roots (zeroes) of :       F(x) = x3-20
Polynomial Roots Calculator is a set of methods aimed at finding values of  x  for which   F(x)=0  

Rational Roots Test is one of the above mentioned tools. It would only find Rational Roots that is numbers  x  which can be expressed as the quotient of two integers

The Rational Root Theorem states that if a polynomial zeroes for a rational number  P/Q   then  P  is a factor of the Trailing Constant and  Q  is a factor of the Leading Coefficient

In this case, the Leading Coefficient is  1  and the Trailing Constant is  -20.

 
The factor(s) are:

of the Leading Coefficient :  1
 
of the Trailing Constant :  1 ,2 ,4 ,5 ,10 ,20

 
Let us test ....

  P  Q  P/Q  F(P/Q)   Divisor
     -1     1      -1.00      -21.00   
     -2     1      -2.00      -28.00   
     -4     1      -4.00      -84.00   
     -5     1      -5.00      -145.00   
     -10     1     -10.00     -1020.00   
     -20     1     -20.00     -8020.00   
     1     1      1.00      -19.00   
     2     1      2.00      -12.00   
     4     1      4.00      44.00   
     5     1      5.00      105.00   
     10     1      10.00      980.00   
     20     1      20.00      7980.00   


Polynomial Roots Calculator found no rational roots

Final result :

  x3 - 20

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