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Solution - Equations reducible to quadratic form

x=5
x=5
x=5
x=-5
x=0.00001.0000i
x=0.0000-1.0000i
x=0.0000+1.0000i
x=0.0000+1.0000i

Step by Step Solution

Reformatting the input :

Changes made to your input should not affect the solution:

 (1): "x2"   was replaced by   "x^2".  1 more similar replacement(s).

Step by step solution :

Step  1  :

Equation at the end of step  1  :

  ((x4) -  (23•3x2)) -  25  = 0 

Step  2  :

Trying to factor by splitting the middle term

 2.1     Factoring  x4-24x2-25 

The first term is,  x4  its coefficient is  1 .
The middle term is,  -24x2  its coefficient is  -24 .
The last term, "the constant", is  -25 

Step-1 : Multiply the coefficient of the first term by the constant   1 • -25 = -25 

Step-2 : Find two factors of  -25  whose sum equals the coefficient of the middle term, which is   -24 .

     -25   +   1   =   -24   That's it


Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above,  -25  and  1 
                     x4 - 25x2 + 1x2 - 25

Step-4 : Add up the first 2 terms, pulling out like factors :
                    x2 • (x2-25)
              Add up the last 2 terms, pulling out common factors :
                     1 • (x2-25)
Step-5 : Add up the four terms of step 4 :
                    (x2+1)  •  (x2-25)
             Which is the desired factorization

Polynomial Roots Calculator :

 2.2    Find roots (zeroes) of :       F(x) = x2+1
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  1.

 
The factor(s) are:

of the Leading Coefficient :  1
 
of the Trailing Constant :  1

 
Let us test ....

  P  Q  P/Q  F(P/Q)   Divisor
     -1     1      -1.00      2.00   
     1     1      1.00      2.00   


Polynomial Roots Calculator found no rational roots

Trying to factor as a Difference of Squares :

 2.3      Factoring:  x2-25 

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 : 25 is the square of 5
Check :  x2  is the square of  x1 

Factorization is :       (x + 5)  •  (x - 5) 

Equation at the end of step  2  :

  (x2 + 1) • (x + 5) • (x - 5)  = 0 

Step  3  :

Theory - Roots of a product :

 3.1    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 :

 3.2      Solve  :    x2+1 = 0 

 
Subtract  1  from both sides of the equation : 
 
                     x2 = -1
 
 
When two things are equal, their square roots are equal. Taking the square root of the two sides of the equation we get:  
 
                     x  =  ± √ -1  

 
In Math,  i  is called the imaginary unit. It satisfies   i2  =-1. Both   i   and   -i   are the square roots of   -1 
The equation has no real solutions. It has 2 imaginary, or complex solutions.

                      x=  0.0000 + 1.0000
                      x=  0.0000 - 1.0000

Solving a Single Variable Equation :

 3.3      Solve  :    x+5 = 0 

 
Subtract  5  from both sides of the equation : 
 
                     x = -5

Solving a Single Variable Equation :

 3.4      Solve  :    x-5 = 0 

 
Add  5  to both sides of the equation : 
 
                     x = 5

Supplement : Solving Quadratic Equation Directly

Solving    x4-24x2-25  = 0   directly 

Earlier we factored this polynomial by splitting the middle term. let us now solve the equation by Completing The Square and by using the Quadratic Formula

Solving a Single Variable Equation :

Equations which are reducible to quadratic :

 4.1     Solve   x4-24x2-25 = 0

This equation is reducible to quadratic. What this means is that using a new variable, we can rewrite this equation as a quadratic equation Using  w , such that  w = x2  transforms the equation into :
 w2-24w-25 = 0

Solving this new equation using the quadratic formula we get two real solutions :
   25.0000  or  -1.0000

Now that we know the value(s) of  w , we can calculate  x  since  x  is  √ w  

Doing just this we discover that the solutions of
   x4-24x2-25 = 0
  are either : 
  x =√25.000 = 5.00000  or :
  x =√25.000 = -5.00000  or :
  x =√-1.000 = 0.0 + 1.00000 i  or :
  x =√-1.000 = 0.0 - 1.00000 i

Four solutions were found :

  1.  x = 5
  2.  x = -5
  3.   x=  0.0000 - 1.0000
  4.   x=  0.0000 + 1.0000

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