Year 8 Factorising Expressions (Common Factors) Worksheet — Level 2 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 8 algebraic expressions worksheet.
Year 8 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: 54a − 63b
Answer: 9(6a − 7b)
- Highest common factor: 9
- 54a − 63b = 9(6a − 7b)
- Check by expanding the brackets.
2.Factorise fully: 20x2 + 16x
Answer: 4x(5x + 4)
- Highest common factor: 4x
- 20x2 + 16x = 4x(5x + 4)
- Check by expanding the brackets.
3.Factorise fully: 15a − 40b
Answer: 5(3a − 8b)
- Highest common factor: 5
- 15a − 40b = 5(3a − 8b)
- Check by expanding the brackets.
4.Factorise fully: 10x2 − 12x
Answer: 2x(5x − 6)
- Highest common factor: 2x
- 10x2 − 12x = 2x(5x − 6)
- Check by expanding the brackets.
5.Factorise fully: 8m + 18n
Answer: 2(4m + 9n)
- Highest common factor: 2
- 8m + 18n = 2(4m + 9n)
- Check by expanding the brackets.
6.Factorise fully: 4x2 − 24x
Answer: 4x(x − 6)
- Highest common factor: 4x
- 4x2 − 24x = 4x(x − 6)
- Check by expanding the brackets.
7.Factorise fully: 10x − 4y
Answer: 2(5x − 2y)
- Highest common factor: 2
- 10x − 4y = 2(5x − 2y)
- Check by expanding the brackets.
8.Factorise fully: 4x2 − 2x
Answer: 2x(2x − 1)
- Highest common factor: 2x
- 4x2 − 2x = 2x(2x − 1)
- Check by expanding the brackets.
9.Factorise fully: 40x + 56y
Answer: 8(5x + 7y)
- Highest common factor: 8
- 40x + 56y = 8(5x + 7y)
- Check by expanding the brackets.
10.Factorise fully: 18x2 − 15x
Answer: 3x(6x − 5)
- Highest common factor: 3x
- 18x2 − 15x = 3x(6x − 5)
- Check by expanding the brackets.
11.Factorise fully: 20m + 28n
Answer: 4(5m + 7n)
- Highest common factor: 4
- 20m + 28n = 4(5m + 7n)
- Check by expanding the brackets.
12.Factorise fully: 3x2 + 8x
Answer: x(3x + 8)
- Highest common factor: x
- 3x2 + 8x = x(3x + 8)
- 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.