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Saturday, 19 April 2014

Quadratic Expression (Chap 3.1)

Quadratic Expression

*The general form of a quadratic expression in one variable is:
             a + bx +c
             where x is the variable, a v and c are constants and a0.



  • Addition and Subtraction of Quadratic Expressions

       a) Example: 4 + 2 

        Therefore,  4 + 2 =6 


       

       b) Example: 4 + (-2 )
  
        Therefore, 4 + (-2 ) =2 


       c) Example: -4 -2x+3 +x+2


        First, you would have to group like terms together

   
       = -4 + 3 -2x+x+2 

        Then, you solve it.


        = - -x+2



  • Negative of a Quadratic Equation
                  -To find the negative of a quadratic expression, we flip all signs. 

a) Example: -(2 +x-1)

Therefore, -(2 +x-1) = -2 -x+1

*We can also simplify quadratic expressions involving the negative of a quadratic expression. 


b) (2x² - 3x +1) - (x²-2x-3) 

Start by expanding the right part 

= 2x² - 3x +1 - x²+2x+3 

Then grouping like terms together

= 2x² - x² - 3x + 2x +1 + 3 

x² - x + 4

  • Expansion and Simplification of Simple Quadratic Expressions

a ) -x² -x +2 + 3(x² + x - 1) = -x² - x + 2 + 3x² +3x - 3 (expand)
                                          
                                             = -x² + 3x² - x + 3x + 2 - 3 (group like terms)
                                             = 2x² + 2x - 1











*Youtube Video:http://www.youtube.com/watch?v=zb7pBanmwr4


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