SOLUTION: <pre> Simplify the expression: x² - 9 4x² - 12x + 36 ———————————— × ———————————————— 2x² - 8x + 6 x³ + 27</pre>

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Question 38537This question is from textbook
:
    Simplify the expression: 

   x² - 9       4x² - 12x + 36 
———————————— × ————————————————
2x² - 8x + 6        x³ + 27
This question is from textbook

Answer by AnlytcPhil(1806) About Me  (Show Source):
You can put this solution on YOUR website!


   x² - 9       4x² - 12x + 36 
———————————— × ————————————————
2x² - 8x + 6        x³ + 27

Factor each numerator and denominator:

Left numerator:     x² - 9 = x² - 3² = (x - 3)(x + 3)

Left denominator:   2x² - 8x + 6 = 2(x² - 4x + 3) = 2(x - 3)(x - 1)

Right numerator:    4x² - 12x + 36 = 4(x² - 3x + 9)

Right denominator:  x³ + 27 = x³ + 3³ = (x + 3)(x² - 3x + 9)

  (x - 3)(x + 3)        4(x² - 3x + 9)
————————————————— × ——————————————————————                
 2(x - 3)(x - 1)     (x + 3)(x² - 3x + 9)

Indicate multiplication of numerators and denominators:

     4(x - 3)(x + 3)(x² - 3x + 9)
—————————————————————————————————————                
 2(x - 3)(x - 1)(x + 3)(x² - 3x + 9)

Cancel 2 and 4

     2
     4(x - 3)(x + 3)(x² - 3x + 9)
—————————————————————————————————————                
 2(x - 3)(x - 1)(x + 3)(x² - 3x + 9)
 1

Cancel the (x - 3)'s

     2   1 
     4(x - 3)(x + 3)(x² - 3x + 9)
—————————————————————————————————————                
 2(x - 3)(x - 1)(x + 3)(x² - 3x + 9)
 1   1

Cancel the (x + 3)'s

     2   1      1
     4(x - 3)(x + 3)(x² - 3x + 9)
—————————————————————————————————————                
 2(x - 3)(x - 1)(x + 3)(x² - 3x + 9)
 1   1             1

Cancel the (x² - 3x + 9)'s

     2   1      1          1
     4(x - 3)(x + 3)(x² - 3x + 9)
—————————————————————————————————————                
 2(x - 3)(x - 1)(x + 3)(x² - 3x + 9)
 1   1             1         1

                 2
              ———————
               x - 1 

Edwin
AnlytcPhil@aol.com