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Solution - Linear equations with one unknown

x=root[3]4.500=1.65096
x=root[3]{4.500}=1.65096
x=0
x=0

Step by Step Solution

Reformatting the input :

Changes made to your input should not affect the solution:

 (1): "x4"   was replaced by   "x^4".  1 more similar replacement(s).

Rearrange:

Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :

                     9*(x^1)-(2*x^4)=0 

Step by step solution :

Step  1  :

Equation at the end of step  1  :

  (9 • (x1)) -  2x4  = 0 

Step  2  :

Equation at the end of step  2  :

  32x -  2x4  = 0 

Step  3  :

Step  4  :

Pulling out like terms :

 4.1     Pull out like factors :

   9x - 2x4  =   -x • (2x3 - 9) 

Trying to factor as a Difference of Cubes:

 4.2      Factoring:  2x3 - 9 

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 :  2  is not a cube !!

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

Polynomial Roots Calculator :

 4.3    Find roots (zeroes) of :       F(x) = 2x3 - 9
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  2  and the Trailing Constant is  -9.

 
The factor(s) are:

of the Leading Coefficient :  1,2
 
of the Trailing Constant :  1 ,3 ,9

 
Let us test ....

  P  Q  P/Q  F(P/Q)   Divisor
     -1     1      -1.00      -11.00   
     -1     2      -0.50      -9.25   
     -3     1      -3.00      -63.00   
     -3     2      -1.50      -15.75   
     -9     1      -9.00     -1467.00   
     -9     2      -4.50      -191.25   
     1     1      1.00      -7.00   
     1     2      0.50      -8.75   
     3     1      3.00      45.00   
     3     2      1.50      -2.25   
     9     1      9.00      1449.00   
     9     2      4.50      173.25   


Polynomial Roots Calculator found no rational roots

Equation at the end of step  4  :

  -x • (2x3 - 9)  = 0 

Step  5  :

Theory - Roots of a product :

 5.1    A product of several terms equals zero. 

 
When a product of two or more terms equals zero, then at least one of the terms must be zero. 

 
We shall now solve each term = 0 separately 

 
In other words, we are going to solve as many equations as there are terms in the product 

 
Any solution of term = 0 solves product = 0 as well.

Solving a Single Variable Equation :

 5.2      Solve  :    -x = 0 

 
Multiply both sides of the equation by (-1) :  x = 0


Solving a Single Variable Equation :

 5.3      Solve  :    2x3-9 = 0 

 
Add  9  to both sides of the equation : 
 
                     2x3 = 9
Divide both sides of the equation by 2:
                     x3 = 9/2 = 4.500
When two things are equal, their cube roots are equal. Taking the cube root of the two sides of the equation we get:  
 
                     x  =  ∛ 9/2  

 
The equation has one real solution
This solution is  x = ∛ 4.500 = 1.65096

Two solutions were found :

  1.  x = ∛ 4.500 = 1.65096
  2.  x = 0

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