like terms

1. Collecting Like Terms
Learning Objective:
Be able to simplify expressions by collecting like
terms

2. Starter
• I go to the shop and I buy 5 cans of Xenon
• I then go to another shop and buy another 3 cans
of Xenon.
• I go to the third shop and buy 2 more cans of
Xenon.
• Is there an easier way to buy all the cans of
Xenon ?

3. Two pipes of lengths 5a and 3a
are joined together
5a 3a
• The total length = 5a + 3a = 8a
• 5a and 3a are like terms

4. Write the total lengths of
these pipes when the two
parts are joined together
• 6x + 4x =
• 5y + 2y =

5. Simplify these expressions
2a) 2n + 3n + n
2b)4p + 2p – p
2c) 8q – 2q – 3q
2d) 5t + 3t + 4t
2e) 7r – 5r – r
2f) 6s – 4s – s
2g) 8x – 5x – 3x
2h) 5x – 6x + 3x
2i) 6y – 8y + 9y

6. Simplify this expression
• 3x2
+ 2x -x2
+ x2
+4x + 5x2
• Like terms in x: 2x + 4x = 6x
• Like terms in x2
: 3x2
-x2
+5x2
= 8x2
• So, 3x2
+ 2x -x2
+ x2
+4x + 5x2
= 6x +
8x2

7. Simplify this expression
• 3x2
+ 2x -x2
+ x2
+4x + 5x2
• Like terms in x: 2x + 4x = 6x
• Like terms in x2
: 3x2
-x2
+5x2
= 8x2
• So, 3x2
+ 2x -x2
+ x2
+4x + 5x2
= 6x +
8x2