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Solution - Simplification or other simple results

(2x9)(4x2+18x+81)
(2x-9)*(4x^2+18x+81)

Step by Step Solution

Step  1  :

Equation at the end of step  1  :

  23x3 -  729

Step  2  :

Trying to factor as a Difference of Cubes:

 2.1      Factoring:  8x3-729 

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 :  8  is the cube of  2 

Check :  729  is the cube of   9 
Check :  x3 is the cube of   x1

Factorization is :
             (2x - 9)  •  (4x2 + 18x + 81) 

Trying to factor by splitting the middle term

 2.2     Factoring  4x2 + 18x + 81 

The first term is,  4x2  its coefficient is  4 .
The middle term is,  +18x  its coefficient is  18 .
The last term, "the constant", is  +81 

Step-1 : Multiply the coefficient of the first term by the constant   4 • 81 = 324 

Step-2 : Find two factors of  324  whose sum equals the coefficient of the middle term, which is   18 .

     -324   +   -1   =   -325
     -162   +   -2   =   -164
     -108   +   -3   =   -111
     -81   +   -4   =   -85
     -54   +   -6   =   -60
     -36   +   -9   =   -45


For tidiness, printing of 24 lines which failed to find two such factors, was suppressed

Observation : No two such factors can be found !!
Conclusion : Trinomial can not be factored

Final result :

  (2x - 9) • (4x2 + 18x + 81)

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