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: 35a − 42b
Answer: 7(5a − 6b)
- Highest common factor: 7
- 35a − 42b = 7(5a − 6b)
- Check by expanding the brackets.
2.Factorise fully: 6x2 + 16x
Answer: 2x(3x + 8)
- Highest common factor: 2x
- 6x2 + 16x = 2x(3x + 8)
- Check by expanding the brackets.
3.Factorise fully: 12a − 20b
Answer: 4(3a − 5b)
- Highest common factor: 4
- 12a − 20b = 4(3a − 5b)
- Check by expanding the brackets.
4.Factorise fully: 6x2 − 14x
Answer: 2x(3x − 7)
- Highest common factor: 2x
- 6x2 − 14x = 2x(3x − 7)
- Check by expanding the brackets.
5.Factorise fully: 5x + 15y
Answer: 5(x + 3y)
- Highest common factor: 5
- 5x + 15y = 5(x + 3y)
- Check by expanding the brackets.
6.Factorise fully: 3x2 − 18x
Answer: 3x(x − 6)
- Highest common factor: 3x
- 3x2 − 18x = 3x(x − 6)
- Check by expanding the brackets.
7.Factorise fully: 36a − 30b
Answer: 6(6a − 5b)
- Highest common factor: 6
- 36a − 30b = 6(6a − 5b)
- Check by expanding the brackets.
8.Factorise fully: 6x2 − 48x
Answer: 6x(x − 8)
- Highest common factor: 6x
- 6x2 − 48x = 6x(x − 8)
- Check by expanding the brackets.
9.Factorise fully: 24m + 16n
Answer: 8(3m + 2n)
- Highest common factor: 8
- 24m + 16n = 8(3m + 2n)
- Check by expanding the brackets.
10.Factorise fully: 12x2 + 42x
Answer: 6x(2x + 7)
- Highest common factor: 6x
- 12x2 + 42x = 6x(2x + 7)
- Check by expanding the brackets.
11.Factorise fully: 5x + 10y
Answer: 5(x + 2y)
- Highest common factor: 5
- 5x + 10y = 5(x + 2y)
- Check by expanding the brackets.
12.Factorise fully: 3x2 − 3x
Answer: 3x(x − 1)
- Highest common factor: 3x
- 3x2 − 3x = 3x(x − 1)
- 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.