1. Combining Like Terms

2. Like Terms
Terms in an expression are like terms if they have identical variable parts.
You can combine terms that are alike.

3. 3x 4x -2y 0.5y 2ab 6ba LIKE LIKE LIKE These are like terms.
We write variables in
alphabetical order.

4. 3xy -9xy LIKE These are like terms even though
they contain both an x and a y.
3xy
-9xy
LIKE

5. 4x 4y unlike Different types of variables are unlike terms.
To be like terms, the variable part
is what has to be the same,
not the numbers.
unlike

6. To be like terms, the variable part4x
8x2
To be like terms, the variable part
and its exponent has to
be the same.
unlike

7. 2xy - x2y 1 unlike The variable part is what has
to be the same, not the numbers.
unlike

8. These are also like terms.xy 1 1 yx
LIKE
We write variables in
alphabetical order.

9. Add or subtract the coefficients.
variables xy yx 5 -3
LIKE
coefficients
To COMBINE LIKE TERMS,
Add or subtract the coefficients.

10. Add or subtract the coefficients.xy yx + 5 -3
=2xy
To COMBINE LIKE TERMS,
Add or subtract the coefficients.

13. Suppose we have:
It could also be:
This is the commutative property.

14. Or:
Commutative property again

15. 1. 2. 3. 4.

16. 5. 6. 7. 8.

17. 9.
4x + 2(3 – x) – 5
= 4x + 2(3) – 2(x) – 5
= 4x + 6 – 2x – 5
= 2x + 1

18. Classwork Practice
Page 78 #11-20
Homework
Page 78 #21-31
79 # 36-41