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Solution - Nonlinear equations

x=root[3]30=3.1072
x=root[3]{30}=3.1072

Other Ways to Solve

Nonlinear equations

Step by Step Solution

Step by step solution :

Step  1  :

Trying to factor as a Difference of Cubes:

 1.1      Factoring:  x3-30 

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 :  30  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) = x3-30
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  -30.

 
The factor(s) are:

of the Leading Coefficient :  1
 
of the Trailing Constant :  1 ,2 ,3 ,5 ,6 ,10 ,15 ,30

 
Let us test ....

  P  Q  P/Q  F(P/Q)   Divisor
     -1     1      -1.00      -31.00   
     -2     1      -2.00      -38.00   
     -3     1      -3.00      -57.00   
     -5     1      -5.00      -155.00   
     -6     1      -6.00      -246.00   
     -10     1     -10.00     -1030.00   
     -15     1     -15.00     -3405.00   
     -30     1     -30.00     -27030.00   
     1     1      1.00      -29.00   
     2     1      2.00      -22.00   
     3     1      3.00      -3.00   
     5     1      5.00      95.00   
     6     1      6.00      186.00   
     10     1      10.00      970.00   
     15     1      15.00      3345.00   
     30     1      30.00     26970.00   


Polynomial Roots Calculator found no rational roots

Equation at the end of step  1  :

  x3 - 30  = 0 

Step  2  :

Solving a Single Variable Equation :

 2.1      Solve  :    x3-30 = 0 

 
Add  30  to both sides of the equation : 
 
                     x3 = 30
When two things are equal, their cube roots are equal. Taking the cube root of the two sides of the equation we get:  
 
                     x  =  ∛ 30  

 
The equation has one real solution
This solution is  x = ∛30 = 3.1072

One solution was found :

                   x = ∛30 = 3.1072

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