Year 10 Factorising and Solving Quadratics Worksheet — Level 2 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 10 quadratics worksheet.
Year 10 Factorising and Solving Quadratics Worksheet — Level 2 — Practice Set 3 — Answers
Factorise, then use the null factor law.
1.Solve: x2 − 81 = 0
Answer: x = 9 or x = −9
- Factorise: (x − 9)(x + 9) = 0
- Null factor law: x − 9 = 0 or x + 9 = 0
- x = 9 or x = −9
2.Solve: x2 − 3x − 10 = 0
Answer: x = −2 or x = 5
- Factorise: (x + 2)(x − 5) = 0
- Null factor law: x + 2 = 0 or x − 5 = 0
- x = −2 or x = 5
3.Solve: x2 + 6x + 8 = 0
Answer: x = −4 or x = −2
- Factorise: (x + 4)(x + 2) = 0
- Null factor law: x + 4 = 0 or x + 2 = 0
- x = −4 or x = −2
4.Solve: x2 + 4x − 21 = 0
Answer: x = 3 or x = −7
- Factorise: (x − 3)(x + 7) = 0
- Null factor law: x − 3 = 0 or x + 7 = 0
- x = 3 or x = −7
5.Solve: x2 + x − 42 = 0
Answer: x = −7 or x = 6
- Factorise: (x + 7)(x − 6) = 0
- Null factor law: x + 7 = 0 or x − 6 = 0
- x = −7 or x = 6
6.Solve: x2 + 9x + 8 = 0
Answer: x = −1 or x = −8
- Factorise: (x + 1)(x + 8) = 0
- Null factor law: x + 1 = 0 or x + 8 = 0
- x = −1 or x = −8
7.Solve: x2 − 6x − 7 = 0
Answer: x = −1 or x = 7
- Factorise: (x + 1)(x − 7) = 0
- Null factor law: x + 1 = 0 or x − 7 = 0
- x = −1 or x = 7
8.Solve: x2 + 6x + 9 = 0
Answer: x = −3 or x = −3
- Factorise: (x + 3)(x + 3) = 0
- Null factor law: x + 3 = 0 or x + 3 = 0
- x = −3 or x = −3
9.Solve: x2 − 8x + 12 = 0
Answer: x = 6 or x = 2
- Factorise: (x − 6)(x − 2) = 0
- Null factor law: x − 6 = 0 or x − 2 = 0
- x = 6 or x = 2
10.Solve: x2 − 3x + 2 = 0
Answer: x = 2 or x = 1
- Factorise: (x − 2)(x − 1) = 0
- Null factor law: x − 2 = 0 or x − 1 = 0
- x = 2 or x = 1
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.