Addition and Subtraction of Algebraic Expressions
Learn how to combine algebraic expressions by adding and subtracting like terms — a fundamental skill in algebra!
🔑 Key Principle: Like Terms
Golden Rule: You can ONLY add or subtract like terms!
Like terms have the same variables with the same powers.
✓ Like Terms
3x and 5x
7ab and 2ab
4y² and −2y²
✗ Unlike Terms
2a and 2b
3x and 3x²
5xy and 5x
🧮 Combining Like Terms
To combine like terms:
- Add or subtract the coefficients (the numbers)
- Keep the literal part the same (the variables)
| Expression | Process | Result |
|---|---|---|
3x + 5x |
(3 + 5)x | 8x |
7ab − 2ab |
(7 − 2)ab | 5ab |
−4y + 9y |
(−4 + 9)y | 5y |
📐 Visual Understanding: Like Terms
Interactive visualization — available in the full lesson