1. Combining Like Terms

2. True or False? Explain your answer.
Warm Up
OBJECTIVE: Students will be able to determine if expressions are equivalent by combining like terms.
Language Objective: Students will be able to explain in words how to combine like terms.
True or False? Explain your answer. a. b. c. d.
True
True
False
True

3. Launch- What is the Area?
What is the area of the rectangle? x 4 3 x 4 3 x 7 x 4 3 x 4x 3x 7x +
Area = 4x + 3x
Area = 7x

4. We just combined all the x’s!
Explore- Using Tiles
Think back to the warm up
We just combined all the x’s!
Let each x represent a red tile.
So, how many tiles would we need? x x x
Can we represent 3x another way using tiles? . x x x +

5. + x x x Using your tiles, what would you get if you combined 2x + 4x?
Explore- Using Tiles
Turn and Talk…
Using your tiles, what would you get
if you combined 2x + 4x?
Now
combine! + x x x
Is this the only way to show 6x?

6. + + 3x 3x + 5x + 1 x x x x x Is this the only way to show 6x?
Explore- Using Tiles
Turn and Talk…
Is this the only way to show 6x? + x x + 3x 3x + x x 5x + 1 x

7. y y y y x x x x What would you get if you combined
Explore- Using Tiles
Turn and Talk…
What would you get if you combined
5x + 3y + 2x + y? Use your tiles. y + y y + y x x x + x + + +

8. Identify variables that are the same
Summary- No Tiles
How can we combine
without using tiles?
Identify variables that are the same 5x
5x + 3y + 2x + y + 3y + 2x y +
Commutative Property
Now Combine! +

9. Vocabulary Summary- Vocabulary Example
Term: a single number, variable, or number and variables multiplied together.
are terms in this expression.
Like Terms: terms that have the same variable or power.
and
and

10. Process 5x + 3y 2x + y + 1. Copy the expression
Summary- Process
Process
1. Copy the expression
2. Identify the like terms 5x + 3y 2x + y +
3. Rewrite using the
Commutative Property
4. Combine the variables
that are the same

11. With your partner, write an equivalent expression for the following:
Summary- Quick Check
With your partner, write an equivalent expression for the following:
#1. 4a + 6b + 3a + 9b
#2. 15x – 4x + 12
#3. y + y + y
#4. 5y + 7z
7a + 15b
11x + 12 3y
5y + 7z

12. Practice- Partners
I. Model the following expression by drawing squares Let = x
= y a. b. + +

13. II. Explain why the following statement is true.
Practice- Partners
II. Explain why the following statement is true.
2x and 4y are not like terms, therefore, you cannot combine them.

14. Write an equivalent expression for the following expressions.
Practice- Partners
Write an equivalent expression for the following expressions. 1. 2. 3.

15. IV. Explain Yvonne’s mistake in the following problem.
Practice- Partners
IV. Explain Yvonne’s mistake in the following problem.
Yvonne just added all the numbers together. She can add numbers that are the like terms, 8x and 6x, but not 2 since it does not have an x. .

16. Assessment- Exit Slip
Jose and Amy were asked to combine 7x + 2y + 6y + 3x. Decide who is correct. Explain.
Jose
7x + 2y + 6y + 3x
Amy
7x + 2y + 6y + 3x
Jose’s work
7x + 3x + 2y + 6y
10x + 8y
18xy
7x + 2y + 6y + 3x = 18xy
Amy’s work
7x + 3x + 2y + 6y
10x + 8y
7x + 2y + 6y + 3x = 10x + 8y