cadence58
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(50 points and brainliest.Need help ASAP)
f ( x ) = 9 x ^3 + 2 x^ 2 − 5 x + 4 and g ( x ) = 5 x ^3 − 7 x + 4 . what is f ( x ) − g ( x ) Show all of your steps and write your final answer in factored form.

Respuesta :

JonHenderson55

Answer:  " 2x (2x - 1) (x + 1) " .

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Step-by-step explanation:

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Given:  

  f(x)   =  9x³ + 2x² − 5x  + 4  ;

  g(x)  =  5x³ − 7x + 4 ;

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What is:  f(x) − g(x) ?

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Plug in:  " 9x³ + 2x² − 5x + 4 "  for:  " f(x) " ;

    and:   " (5x³ − 7x + 4) " ;  for:  "g(x)" ;

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→  " f(x) − g(x)   =  

   

       " 9x³ + 2x² − 5x + 4  − (5x³ − 7x + 4) "  .

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Rewrite this expression as:

 →  " 9x³ + 2x² − 5x + 4  − 1(5x³ − 7x + 4) "  .

 →   {since:  " 1 " ;  multiplied by "any value" ;  is equal to that same value.}.

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Now, let us example the following portion of the expression:

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 "  − 1(5x³ − 7x + 4) "

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Note the "distributive property"  of multiplication:

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    →   a(b + c) = ab + ac ;

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Likewise:

     →  a(b + c + d) = ab + ac + ad .

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As such:

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    →  "  − 1(5x³ − 7x + 4)  "  ;

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             =   (-1 * 5x³) + (-1 * 7x) + (-1 * 4) ;

             =  - 5x³  +  (-7x)  +  (-4)  ;

             =   - 5x³  − 7x − 4  ;

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Now, add the "beginning portion of the expression" ; that is:

  " f(x) " ;  to the expression ;  which is:

                        →   9x³ + 2x² − 5x  +  4  ;

 →  as follows:  

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 →  9x³ + 2x² − 5x  +  4 − 5x³ − 7x − 4  ;

 →  {Note that the:  " - " sign; that is;

       the "negative sign", in the term:  " -5x³ " ;

       becomes a: " − " sign; that is; a "minus sign" .}.

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Now, combine the "like terms" of this expression; as follows:

  + 9x³  −  5x³  =  + 4x³ ;

 − 5x − 7x  =  − 2x ;

 + 4 − 4 = 0 ;

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and we have:

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 →     " 4x³  +  2x²  − 2x ".

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Now, to write this answer in "factored form" :

Note that among all 3 (three) terms in this expression, each term has a factor of "2" .  The lowest coefficient among these 3 (three) terms is "2" ;  so we can "factor out" a "2".  

Also, each of the 3 (three) terms in this fraction is a coefficient to a variable.  That variable takes the form of "x".  The term in this expression  with the variable, "x";  with the lowest degree has the variable: "x" (i.e. "x¹ = x" ) ;  so we can "factor out a "2x" (rather than just the number, "2".).

So, by factoring out a "2x" ;  take the first term [among the 3 (three) terms in the expression] —which is:  "4x³ " .

2x * (?)  = 4x³  ?  ;'

↔  [tex]\frac{4x^3}{2x} =[/tex] ? ;

→  4/2 = 2 ;

[tex]\frac{x^{3}}{x} = \frac{x^3}{x^1}  = x^{(3-1)} =  x^{2}[/tex] ;  

As such:   2x * (2x²)  =  4x³ ;

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Now, by factoring out a "2x" ;  take the second term [among the 3 (three) terms in the expression] — which is:  "2x² " .

2x * (?) = 2x²  ? ;

↔   [tex]\frac{2x^{2}}{2x} =[/tex]  ?

→  2/2 = 1 ;

→  [tex]\frac{x^{2}}{x} = \frac{x^2}{x^1}= x^{(2-1)} } = x^1 = x[/tex] ;

As such:  2x * (x) = 2x²

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Now, by factoring out a "2x" ;  take the third term [among the 3 (three) terms in the expression] — which is:  " − 2x " .

2x * (?) =  - 2x ;

↔  [tex]\frac{-2x}{2x} =[/tex] -1 ;

As such:  2x * (-1) =  − 2x .  

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So:

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Given the simplified expression:

 →     " 4x³  +  2x²  − 2x " ;

We can "factor out' a:  " 2x " ;  and write the this answer is: "factored form" ; as:

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  "2x (2x²  +  x  −  1 ) . "

Now, we can further factor the:

    " (2x²  +  x  −  1) " ; portion;

Note:  "(2x² + x - 1)" =

2x² + 2x - 1x -1 = (2x -1) + x (2x - 1 ) =

(2x - 1)  ( x + 1)

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Now, bring down the "2x" ; and write the Full "factored form" ; as follows:

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    →   " 2x (2x - 1) (x + 1) "  .

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Hope this helps!

 Wishing you the best!

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