F2 因式分解問題

2010-09-19 9:58 am
因式分解問題

1.Simplify

 2(x^2)-5x-12   9
------------------- x (2 + ---------)
 4(x^2)-1     x-4

2. a) Factorize (m+2)(m-8)+24
 b) Using the result of (a), factorize (x^2+x+2)(x^2+x-8)+24.

3. a) Factorize a^4+2a^2b^2+b^4
 b) Using the result of (a), factorize a^4+a^2b^2+b^4.

4. Factorize 2(y^3) + (1/4).

回答 (1)

2010-09-19 1:41 pm
✔ 最佳答案
1.Simplify

 2(x^2)-5x-12        9
------------------- x (2 + ---------)
 4(x^2)-1         x-4

 2(x^2)-5x-12   2(x-4)      9
------------------- x (---------- + ---------)
 4(x^2)-1      x-4        x-4

 (2x +3)(x-4)    2(x-4) + 9 
------------------- x (-------------------)
 (2x^2)-1       x-4   

 (2x +3)(x-4)    (2x + 1)
------------------- x (-------------)
 (2x+1)(2x -1)     ( x-4)   

 (2x +3)   
-------------
 (2x -1)   

2. a) Factorize (m+2)(m-8)+24
 b) Using the result of (a), factorize (x^2+x+2)(x^2+x-8)+24.
a) m^2 – 6m -16 +24
m^2 – 6m + 8
(m -4)(m – 2)
b) Let m = x^2+x
(x^2+x+2)(x^2+x-8)+24 = (x^2+x -4) (x^2+x -2)


3. a) Factorize a^4+2a^2b^2+b^4
 b) Using the result of (a), factorize a^4+a^2b^2+b^4.

   a) (a^2 + b^2) (a^2 + b^2)
      ( a +b)(a-b) (a^2 + b^2)

  b) Typo error: cannot be factorized


4. Factorize 2(y^3) + (1/4).
2[(y^3) + (1/8)]
2[(y^3) + (1/2)^3]
2(y + ½)[y^2 –(1/2)(y) + (1/2)^2)]
2(y + ½) (y^2 –y/2 + ¼)


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