Year 8 Factorising Expressions (Common Factors) Worksheet — Level 2 — Practice Set 2 — Answers
Answer sheet with worked solutions for the Year 8 algebraic expressions worksheet.
Year 8 Factorising Expressions (Common Factors) Worksheet — Level 2 — Practice Set 2 — Answers
Find the highest common factor of the terms and write it outside the brackets.
1.Factorise fully: 6a + 2b
Answer: 2(3a + b)
- Highest common factor: 2
- 6a + 2b = 2(3a + b)
- Check by expanding the brackets.
2.Factorise fully: 8x2 + 14x
Answer: 2x(4x + 7)
- Highest common factor: 2x
- 8x2 + 14x = 2x(4x + 7)
- Check by expanding the brackets.
3.Factorise fully: 18x − 6y
Answer: 6(3x − y)
- Highest common factor: 6
- 18x − 6y = 6(3x − y)
- Check by expanding the brackets.
4.Factorise fully: 4x2 − 24x
Answer: 4x(x − 6)
- Highest common factor: 4x
- 4x2 − 24x = 4x(x − 6)
- Check by expanding the brackets.
5.Factorise fully: 15a + 18b
Answer: 3(5a + 6b)
- Highest common factor: 3
- 15a + 18b = 3(5a + 6b)
- Check by expanding the brackets.
6.Factorise fully: 5x2 − 10x
Answer: 5x(x − 2)
- Highest common factor: 5x
- 5x2 − 10x = 5x(x − 2)
- Check by expanding the brackets.
7.Factorise fully: 12a + 21b
Answer: 3(4a + 7b)
- Highest common factor: 3
- 12a + 21b = 3(4a + 7b)
- Check by expanding the brackets.
8.Factorise fully: 5x2 + 3x
Answer: x(5x + 3)
- Highest common factor: x
- 5x2 + 3x = x(5x + 3)
- Check by expanding the brackets.
9.Factorise fully: 9x − 9y
Answer: 9(x − y)
- Highest common factor: 9
- 9x − 9y = 9(x − y)
- Check by expanding the brackets.
10.Factorise fully: 4x2 + 32x
Answer: 4x(x + 8)
- Highest common factor: 4x
- 4x2 + 32x = 4x(x + 8)
- Check by expanding the brackets.
11.Factorise fully: 4a + 2b
Answer: 2(2a + b)
- Highest common factor: 2
- 4a + 2b = 2(2a + b)
- Check by expanding the brackets.
12.Factorise fully: x2 − 6x
Answer: x(x − 6)
- Highest common factor: x
- x2 − 6x = x(x − 6)
- 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.