Combining Like Terms

inAlgebra County

2 - 5- 6 3x x 4x 2

Different types of variables are unlike terms.

4x 8x2unlike

To be like terms, the variable part is what has to be the same,

not the numbers.

Different types of variables are unlike terms.

The variable part is what hasto be the same, not the numbers.

2xy - x2yunlike 1

These are like terms even thoughthey contain both an x and a y.

3xy -9xyLIKE

These are also like terms.

xy yxLIKE 11We write variables in

alphabetical order.

Even if we put numbers in front(coefficients) of each variable,

they are still like terms.

xy yxLIKE5 -3

Suppose we have:

2 3 4x y x3y 2x

It could also be:

2x 3yThis is the commutative property.

3 5 4x x

2 1x

1 2xOr:

Commutative property again

The Adding Song

Sung in

Algebra County

to the tune of

“Hark! The Herald Angels Sing”

When in math we do additionWe must always add like things.To add decimals, we must line upCorresponding place values.To add fractions, we’re in need ofLike denomina-ators,In Algebra, we need like terms;They stay the same after we add,In Algebra, we need like terms;They stay the same after we add.

The Multiplying Song

Sung in

Algebra County

to the tune of

“Hark! The Herald Angels Sing”

When we multiply two termsThey don’t have to be alike.First we multiply the numbers,Next, of course, the variables.When we write the final productHere’s the order of the factors:Number first, the letters next,Recorded alphabetically,Number first, the letters next,Recorded alphabetically.

1. 7(3 )x 21x

2. 2(5 )a 10a

3. 3( 10 )x 30x

4. 4( 4 )y 16y

5. ( 7 )y 7y

Write in notes:

6. 7 (3 )y x 21xy

7. 2 (5 )b a 10ab

8. 3 ( 2 )p r 6 pr

Write in notes:

9. 7 ( 3 )x x 7 3 10x x x

10. 5 ( 3 )a a 5 3 2a a a

11. 7 (3 )x x 7 3 4x x x

12. 11 (5 )y y 11 5 6y y y

13. 7 8 9 2x y y x 9x y 2 214. 3 4x x x 22 4x x

15. 2 5 8 3x x 10 8x

16. 3 4 3y x same

to Algebra County