Collection of like terms 17 May 2019

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

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

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

Exercise Simplify the following expressions 2x + 4 + 3x 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

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 y2 + + 4y + 5y2 – 8y = 6y2 – 4y

Exercise Simplify the following expressions