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Solution - Simplification or other simple results

x32x24x8
x^3-2x^2-4x-8

Step by Step Solution

Step  1  :

Equation at the end of step  1  :

  (((x3) -  4x) -  2x2) -  8

Step  2  :

Checking for a perfect cube :

 2.1    x3-2x2-4x-8  is not a perfect cube

Trying to factor by pulling out :

 2.2      Factoring:  x3-2x2-4x-8 

Thoughtfully split the expression at hand into groups, each group having two terms :

Group 1:  -4x-8 
Group 2:  -2x2+x3 

Pull out from each group separately :

Group 1:   (x+2) • (-4)
Group 2:   (x-2) • (x2)

Bad news !! Factoring by pulling out fails :

The groups have no common factor and can not be added up to form a multiplication.

Polynomial Roots Calculator :

 2.3    Find roots (zeroes) of :       F(x) = x3-2x2-4x-8
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  -8.

 
The factor(s) are:

of the Leading Coefficient :  1
 
of the Trailing Constant :  1 ,2 ,4 ,8

 
Let us test ....

  P  Q  P/Q  F(P/Q)   Divisor
     -1     1      -1.00      -7.00   
     -2     1      -2.00      -16.00   
     -4     1      -4.00      -88.00   
     -8     1      -8.00      -616.00   
     1     1      1.00      -13.00   
     2     1      2.00      -16.00   
     4     1      4.00      8.00   
     8     1      8.00      344.00   


Polynomial Roots Calculator found no rational roots

Final result :

  x3 - 2x2 - 4x - 8

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