Year 8 Factorising Expressions (Common Factors) Worksheet — Level 2 — Answers
Answer sheet with worked solutions for the Year 8 algebraic expressions worksheet.
Year 8 Factorising Expressions (Common Factors) Worksheet — Level 2 — Answers
Find the highest common factor of the terms and write it outside the brackets.
1.Factorise fully: 5m + 25n
Answer: 5(m + 5n)
- Highest common factor: 5
- 5m + 25n = 5(m + 5n)
- Check by expanding the brackets.
2.Factorise fully: 9x2 + 12x
Answer: 3x(3x + 4)
- Highest common factor: 3x
- 9x2 + 12x = 3x(3x + 4)
- Check by expanding the brackets.
3.Factorise fully: 6m + 3n
Answer: 3(2m + n)
- Highest common factor: 3
- 6m + 3n = 3(2m + n)
- Check by expanding the brackets.
4.Factorise fully: 5x2 + 30x
Answer: 5x(x + 6)
- Highest common factor: 5x
- 5x2 + 30x = 5x(x + 6)
- Check by expanding the brackets.
5.Factorise fully: 35x − 28y
Answer: 7(5x − 4y)
- Highest common factor: 7
- 35x − 28y = 7(5x − 4y)
- Check by expanding the brackets.
6.Factorise fully: 8x2 + 18x
Answer: 2x(4x + 9)
- Highest common factor: 2x
- 8x2 + 18x = 2x(4x + 9)
- Check by expanding the brackets.
7.Factorise fully: 28m − 21n
Answer: 7(4m − 3n)
- Highest common factor: 7
- 28m − 21n = 7(4m − 3n)
- Check by expanding the brackets.
8.Factorise fully: 10x2 + 45x
Answer: 5x(2x + 9)
- Highest common factor: 5x
- 10x2 + 45x = 5x(2x + 9)
- Check by expanding the brackets.
9.Factorise fully: 10m + 35n
Answer: 5(2m + 7n)
- Highest common factor: 5
- 10m + 35n = 5(2m + 7n)
- Check by expanding the brackets.
10.Factorise fully: 12x2 + 28x
Answer: 4x(3x + 7)
- Highest common factor: 4x
- 12x2 + 28x = 4x(3x + 7)
- Check by expanding the brackets.
11.Factorise fully: 12m + 54n
Answer: 6(2m + 9n)
- Highest common factor: 6
- 12m + 54n = 6(2m + 9n)
- Check by expanding the brackets.
12.Factorise fully: 12x2 + 20x
Answer: 4x(3x + 5)
- Highest common factor: 4x
- 12x2 + 20x = 4x(3x + 5)
- 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.