Year 9 Factorising Expressions (Common Factors) Worksheet — Level 2 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 9 algebraic expressions worksheet.
Year 9 Factorising Expressions (Common Factors) Worksheet — Level 2 — Practice Set 4 — Answers
Find the highest common factor of the terms and write it outside the brackets.
1.Factorise fully: 12a + 2b
Answer: 2(6a + b)
- Highest common factor: 2
- 12a + 2b = 2(6a + b)
- Check by expanding the brackets.
2.Factorise fully: 3x2 + 18x
Answer: 3x(x + 6)
- Highest common factor: 3x
- 3x2 + 18x = 3x(x + 6)
- Check by expanding the brackets.
3.Factorise fully: 25m + 10n
Answer: 5(5m + 2n)
- Highest common factor: 5
- 25m + 10n = 5(5m + 2n)
- Check by expanding the brackets.
4.Factorise fully: 20x2 + 45x
Answer: 5x(4x + 9)
- Highest common factor: 5x
- 20x2 + 45x = 5x(4x + 9)
- Check by expanding the brackets.
5.Factorise fully: 10x − 14y
Answer: 2(5x − 7y)
- Highest common factor: 2
- 10x − 14y = 2(5x − 7y)
- Check by expanding the brackets.
6.Factorise fully: 24x2 − 42x
Answer: 6x(4x − 7)
- Highest common factor: 6x
- 24x2 − 42x = 6x(4x − 7)
- Check by expanding the brackets.
7.Factorise fully: 18m + 30n
Answer: 6(3m + 5n)
- Highest common factor: 6
- 18m + 30n = 6(3m + 5n)
- Check by expanding the brackets.
8.Factorise fully: 12x2 + 27x
Answer: 3x(4x + 9)
- Highest common factor: 3x
- 12x2 + 27x = 3x(4x + 9)
- Check by expanding the brackets.
9.Factorise fully: 2x − 6y
Answer: 2(x − 3y)
- Highest common factor: 2
- 2x − 6y = 2(x − 3y)
- Check by expanding the brackets.
10.Factorise fully: 12x2 − 32x
Answer: 4x(3x − 8)
- Highest common factor: 4x
- 12x2 − 32x = 4x(3x − 8)
- Check by expanding the brackets.
11.Factorise fully: 18a + 9b
Answer: 9(2a + b)
- Highest common factor: 9
- 18a + 9b = 9(2a + b)
- Check by expanding the brackets.
12.Factorise fully: 2x2 + 3x
Answer: x(2x + 3)
- Highest common factor: x
- 2x2 + 3x = x(2x + 3)
- 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.