Math, asked by ninja38, 1 year ago

f(x)=x^3-x^2-12x+32=2

Answers

Answered by dronamrajurajapcs7q2
0
answer is 0
x3-x2-12x=-32 

Three solutions were found :

 x = -4

 x =(5-√-7)/2=(5-i√ 7 )/2= 2.5000-1.3229i

 x =(5+√-7)/2=(5+i√ 7 )/2= 2.5000+1.3229i

Rearrange:

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

                     x^3-x^2-12*x-(-32)=0 

Step by step solution :

Step  1  :

Checking for a perfect cube :

 1.1    x3-x2-12x+32  is not a perfect cube 

Trying to factor by pulling out :

 1.2      Factoring:  x3-x2-12x+32 

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

Group 1:  x3-x2 
Group 2:  -12x+32 

Pull out from each group separately :

Group 1:   (x-1) • (x2)
Group 2:   (3x-8) • (-4)

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 :

 1.3    Find roots (zeroes) of :       F(x) = x3-x2-12x+32
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  32. 

 The factor(s) are: 

of the Leading Coefficient :  1
 of the Trailing Constant :  1 ,2 ,4 ,8 ,16 ,32 

 Let us test ....

  P  Q  P/Q  F(P/Q)   Divisor     -1     1      -1.00      42.00        -2     1      -2.00      44.00        -4     1      -4.00      0.00    x+4      -8     1      -8.00      -448.00        -16     1     -16.00     -4128.00        -32     1     -32.00     -33376.00        1     1      1.00      20.00        2     1      2.00      12.00        4     1      4.00      32.00        8     1      8.00      384.00        16     1      16.00      3680.00        32     1      32.00     31392.00   


The Factor Theorem states that if P/Q is root of a polynomial then this polynomial can be divided by q*x-p Note that q and p originate from P/Q reduced to its lowest terms 

In our case this means that 
   x3-x2-12x+32 
can be divided with  x+4 

Polynomial Long Division :

 1.4    Polynomial Long Division 
Dividing :  x3-x2-12x+32 
                              ("Dividend")
By         :    x+4    ("Divisor")

dividend  x3 - x2 - 12x + 32 - divisor * x2   x3 + 4x2     remainder  - 5x2 - 12x + 32 - divisor * -5x1   - 5x2 - 20x   remainder      8x + 32 - divisor * 8x0       8x + 32 remainder       0

Quotient :  x2-5x+8  Remainder:  0 

Trying to factor by splitting the middle term

 1.5     Factoring  x2-5x+8 

The first term is,  x2  its coefficient is  1 .
The middle term is,  -5x  its coefficient is  -5 .
The last term, "the constant", is  +8 

Step-1 : Multiply the coefficient of the first term by the constant   1 • 8 = 8 

Step-2 : Find two factors of  8  whose sum equals the coefficient of the middle term, which is   -5 .

     -8   +   -1   =   -9     -4   +   -2   =   -6     -2   +   -4   =   -6     -1   +   -8   =   -9     1   +   8   =   9     2   +   4   =   6     4   +   2   =   6     8   +   1   =   9


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

Equation at the end of step  1  :

(x2 - 5x + 8) • (x + 4) = 0
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