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Simplifying Variable Expressions _Negative Units - Day 2_

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					Simplifying Variable Expressions
(Negative Units - Day 2)


   We are learning to…simplify variable
   expressions by combining like terms.
Negative Units
o   As you are working today you may
    notice negative units.
o   These units may be shown in one of
    two ways.
    n   Adding negative units.
    n   Subtracting positive units.
        n   This is because adding a negative is the
            same as subtracting a positive.
        n   So today pay attention to both the sign and
            the operation involved in the expression.
    Negative Units
o   When representing Negative Units with Algebra
    Tiles you will use the red side of the tile.

               xy
               xy                         xy
                                          xy



        This represents…           This represents…
        Positive xy (+xy)          Negative xy (-xy)
o   When drawing your representations today let:
    n   Colored in tiles represent positive units.
    n   Open tiles represent negative units.
                                           With your team:
                                  • Draw 2 different
                                    representations of 0 with
    Negative Units                  Algebra Tiles.
                                  • Write the expressions that
                                    represent the tiles.


o   Remember…when a positive unit and a negative unit are put
    together we create a…

                       ZERO PAIR
      For example the expression below would represent zero:

                      x2
                      x2        +         x2
                                          x2


        This expression could be written two different ways:

         x2 + (-x2) = 0         OR         x2 – x2 = 0
               Simplify the expression below:

          -2x + 3y – 3x + (-x2) – y + 4x2
Organize the Algebra Tiles so that similar units are next to
      Represent the Make Zero Pairs: Algebra Tiles:
                    expression with
                      one another:
                             x
                             x
x x                                             x2
                                                x2      x2
                                                        x2
x x
              yy         x
         yy         y    x       x
                                 x   x2
                                     x2
                   y                      yy

                                                x2
                                                x2      x2
                                                        x2




      Write the simplified version of the expression:


                        2y – 5x + 3x2
                Simplify the expression below:

          xy + 4 – 2y2 – 2xy + (-4) – 2y2
Organize the Algebra Tiles so that similar units are next to
      Represent the Make Zero Pairs: Algebra Tiles:
                    expression with
                      one another:


            1
            1         y2            xy
                                    xy       1
                                             1       y2
                                                    y2
                     y2

  xy        1
            1
  xy                                         1
                                             1
            1
            1
                            y2               1
                                             1             y2
                                                          y2
                           y2        xy
                                     xy
            1
            1                                1
                                             1


       Write the simplified version of the expression:

                       -xy – 4y2
                  Practice…
• Now try some practice with your team.
• Directions:
    – Read each expression carefully.
    – Use your Algebra Tiles to create a
      representation of the expression.
    – Draw your representation with Algebra Tiles.
    – Organize your tiles so that you combine like
      terms in the expression.
    – Create Zero Pairs.
    – Write your simplified expression.

				
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posted:7/26/2013
language:English
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