1. Collection of like terms
17 May 2019

2. To simplify a string of algebra terms (called an expression) it is possible to add/subtract letters which are the same.
Examples:
2a + 5a – 3a = 4a
3w – 8w + 10w = 5w
y + 5y – 8y = – 2y

3. Exercises
Simplify these algebraic expressions
(i) a + a + a
3b + 2b - b
15e – 8e + 6e
4m + 6m – 2m
9n – 6n + 2n
5y – 6y – 2y + y

4. If an expression contains more than one letter we must remember that it is only possible to collect (add/subtract) the terms that are the same.
Examples:
7a + 5g – 3a + 2g = 4a + 7g
3r – 8w + 6r + 5w = 9r – 3w
y – 2b + 2y – 4b = 3y – 6b

5. Exercise
Simplify the following expressions
2x x
9 – 2x + 1
5c + 2d – 3c + d
5f – 3g -7f + 9g + 3f – 4g
7m – 2n + 6 – 5m + 7n + 3
7h + 3k + 2 – 4k – 2h
6p – 2q + 4r – 2p – 3q + r
12h – 6i + 3h – 3i

6. Note: x2 and x are not considered like terms and therefore cannot be collected together.
This rule applies to all letters
Examples:
5a2 + 5a – 3a2 = 2a2 + 5a
3w2 – 3w + 10w2 + 8w = 13w2 + 5w
y y + 5y2 – 8y = 6y2 – 4y

7. Exercise
Simplify the following expressions