To simplify an expression with brackets, expand each bracket first, then collect like terms. 4(3a − 5) + 2(2a − 5) = 12a − 20 + 4a − 10.
Now collect: 12a + 4a = 16a and −20 − 10 = −30, so the answer is 16a − 30. Be careful with a negative outside a bracket: −3(x − 2) = −3x + 6, because a negative times a negative is positive.
Worked example
Simplify 5(2p + 3) − 2(p − 4)
- Expand: 10p + 15 − 2p + 8.
- Collect: 10p − 2p = 8p and 15 + 8 = 23.
Answer:8p + 23
Key words
- expand
- multiply out brackets
- like terms
- terms with the same letters
- coefficient
- the number in front of a letter
Practise this
New questions every time.
Common Core-referenced: 7.EE.A.1