Lesson Notes 26.8.2010

In order to let y=0, the x in the following equations have to be:
1. y=2x-2
x=1
2. y=x+2
x=-2
3. y=(2x-2)(x+2)
y=(2x1-2)(-2+2)
  =0x0
Thus, y=0
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y=(3x-5)(x-4)
y=20 
because (-5)(-4)=20
y=x^2-x-2
  =(x ?*) (x ?~)
Steps to find the values of “?*” and “?~”
---> The product of ?* and ?~ has to be -2.
  1. List down all the possibilities (The product of ?* and ?~ values is -2)
  2. In this case, the sum of ?* and ?~ has to be -1
  3. Choose the correct possibility
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If the equation is y=x^2 -6x+8
                              = (x ?*) (x ?~)
-----> The product of ?* and ?~ has to be 8
------> The sum of ?* and ?~ has to be -6
  1. List down all the possibilities (The product of ?* and ?~ values is -2)
  2. In this case, the sum of ?* and ?~ has to be -6
  3. Choose the correct possibility (so that the product of ?* and ?~ values is -2 &  the sum of ?* and ?~ is -6
Ans: -2 & -4

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