1. Simplifying Variable Expressions (Negative Units - Day 2) We are learning to…simplify variable expressions by combining like terms. Saturday, August 08, 2015

2. Negative Units  As you are working today you may notice negative units.  These units may be shown in one of two ways. 1.Adding negative units. 2.Subtracting positive units. This is because adding a negative is the same as subtracting a positive. So today pay attention to both the sign and the operation involved in the expression.

3. Negative Units  When representing Negative Units with Algebra Tiles you will use the red side of the tile.  When drawing your representations today let: Colored in tiles represent positive units. Open tiles represent negative units. xy This represents… Positive xy (+xy) This represents… Negative xy (-xy)

4. Negative Units  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: x2x2 x2x2 + x2x2 x2x2 This expression could be written two different ways: x 2 + (-x 2 ) = 0 OR x 2 – x 2 = 0 With your team: 1.Draw 2 different representations of 0 with Algebra Tiles. 2.Write the expressions that represent the tiles.

5. Simplify the expression below: 2y2y Represent the expression with Algebra Tiles: Organize the Algebra Tiles so that similar units are next to one another: Write the simplified version of the expression: -2x + 3y – 3x + (-x 2 ) – y + 4x 2 x x y y x x y y y y x x x x x x y y x2x2 x2x2 x2x2 x2x2 x2x2 x2x2 x2x2 x2x2 x2x2 x2x2 Make Zero Pairs: – 5x + 3x 2

6. Simplify the expression below: -xy Represent the expression with Algebra Tiles: Organize the Algebra Tiles so that similar units are next to one another: Write the simplified version of the expression: xy + 4 – 2y 2 – 2xy + (-4) – 2y 2 Make Zero Pairs: – 4y 2 1 1 xy 1 1 1 1 1 1 y2y2 y2y2 y2y2 y2y2 y2y2 y2y2 y2y2 y2y2 1 1 1 1 1 1 1 1

7. Practice… Now try some practice with your team. Directions: 1.Read each expression carefully. 2.Use your Algebra Tiles to create a representation of the expression. 3.Draw your representation with Algebra Tiles. 4.Organize your tiles so that you combine like terms in the expression. 5.Create Zero Pairs. 6.Write your simplified expression.