Year 9 Factorising Expressions (Common Factors) Worksheet — Level 2 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 9 algebraic expressions worksheet.
Year 9 Factorising Expressions (Common Factors) Worksheet — Level 2 — Practice Set 3 — Answers
Find the highest common factor of the terms and write it outside the brackets.
1.Factorise fully: 45a − 63b
Answer: 9(5a − 7b)
- Highest common factor: 9
- 45a − 63b = 9(5a − 7b)
- Check by expanding the brackets.
2.Factorise fully: 24x2 + 4x
Answer: 4x(6x + 1)
- Highest common factor: 4x
- 24x2 + 4x = 4x(6x + 1)
- Check by expanding the brackets.
3.Factorise fully: 4x + 10y
Answer: 2(2x + 5y)
- Highest common factor: 2
- 4x + 10y = 2(2x + 5y)
- Check by expanding the brackets.
4.Factorise fully: 10x2 − 25x
Answer: 5x(2x − 5)
- Highest common factor: 5x
- 10x2 − 25x = 5x(2x − 5)
- Check by expanding the brackets.
5.Factorise fully: 36m − 30n
Answer: 6(6m − 5n)
- Highest common factor: 6
- 36m − 30n = 6(6m − 5n)
- Check by expanding the brackets.
6.Factorise fully: 4x2 − 7x
Answer: x(4x − 7)
- Highest common factor: x
- 4x2 − 7x = x(4x − 7)
- Check by expanding the brackets.
7.Factorise fully: 45x + 81y
Answer: 9(5x + 9y)
- Highest common factor: 9
- 45x + 81y = 9(5x + 9y)
- Check by expanding the brackets.
8.Factorise fully: x2 + 4x
Answer: x(x + 4)
- Highest common factor: x
- x2 + 4x = x(x + 4)
- Check by expanding the brackets.
9.Factorise fully: 8m − 56n
Answer: 8(m − 7n)
- Highest common factor: 8
- 8m − 56n = 8(m − 7n)
- Check by expanding the brackets.
10.Factorise fully: 15x2 − 6x
Answer: 3x(5x − 2)
- Highest common factor: 3x
- 15x2 − 6x = 3x(5x − 2)
- Check by expanding the brackets.
11.Factorise fully: 4a − 12b
Answer: 4(a − 3b)
- Highest common factor: 4
- 4a − 12b = 4(a − 3b)
- Check by expanding the brackets.
12.Factorise fully: 20x2 − 28x
Answer: 4x(5x − 7)
- Highest common factor: 4x
- 20x2 − 28x = 4x(5x − 7)
- Check by expanding the brackets.
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.