1. Combining Like Terms
8th Pre-Algebra

2. Warm up Simplify. 9 + 13 – 5 + 3 16 - 8 + 4 -1 6 + 9 – 10 + 3
– 20 – 2

3. Check HW

4. Vocabulary
Term
Like term
Equivalent expression
Simplify

5. Combine like terms to simplify
14a – 5a
7y + 8 – 3y y
3x x
13k + 6 – 8k k

6. 9x + 3y – 2x + 5
5t + 7p – 3p – 2t
4m + 9n – 2
k + 3n – 2n + 4k

7. Simplify Simplify algebraic expressions by combining like terms.
6(5 + n) – 2n
4(y + 9) – 3y
4(3x + 6) – 7x
6(x + 5) + 3x

8. Solving equations Solve the equation by combining like terms.
8x – x = 112
x + 3x = 48
6y + y = 42

9. Write What is the first step in simplifying the expression
2 + 8(3y + 5) – y
Explain why 8x + 8y + 8 is already simplified.

10. What is the error?
A student said that 2x + 3y can be simplified to 5xy by combining like terms. What error did the student make?

11. HW
Textbook p. 30 (25-36 all)