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Year 12 Factorising and Solving Quadratics Worksheet — Level 2 — Practice Set 2 — Answers

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Success TutoringWorksheetsAnswer sheetYear 12 · Mathematics · Quadratics

Year 12 Factorising and Solving Quadratics Worksheet — Level 2 — Practice Set 2 — Answers

Factorise, then use the null factor law.

1.Solve: x2 + 10x + 16 = 0

Answer: x = −2 or x = −8

  1. Factorise: (x + 2)(x + 8) = 0
  2. Null factor law: x + 2 = 0 or x + 8 = 0
  3. x = −2 or x = −8
2.Solve: x2 − 49 = 0

Answer: x = 7 or x = −7

  1. Factorise: (x − 7)(x + 7) = 0
  2. Null factor law: x − 7 = 0 or x + 7 = 0
  3. x = 7 or x = −7
3.Solve: x2 + 9x + 20 = 0

Answer: x = −4 or x = −5

  1. Factorise: (x + 4)(x + 5) = 0
  2. Null factor law: x + 4 = 0 or x + 5 = 0
  3. x = −4 or x = −5
4.Solve: x2 + 4x − 21 = 0

Answer: x = −7 or x = 3

  1. Factorise: (x + 7)(x − 3) = 0
  2. Null factor law: x + 7 = 0 or x − 3 = 0
  3. x = −7 or x = 3
5.Solve: x2 + 8x − 9 = 0

Answer: x = 1 or x = −9

  1. Factorise: (x − 1)(x + 9) = 0
  2. Null factor law: x − 1 = 0 or x + 9 = 0
  3. x = 1 or x = −9
6.Solve: x2 + 10x + 24 = 0

Answer: x = −6 or x = −4

  1. Factorise: (x + 6)(x + 4) = 0
  2. Null factor law: x + 6 = 0 or x + 4 = 0
  3. x = −6 or x = −4
7.Solve: x2 + 11x + 30 = 0

Answer: x = −6 or x = −5

  1. Factorise: (x + 6)(x + 5) = 0
  2. Null factor law: x + 6 = 0 or x + 5 = 0
  3. x = −6 or x = −5
8.Solve: x2 − 10x + 16 = 0

Answer: x = 8 or x = 2

  1. Factorise: (x − 8)(x − 2) = 0
  2. Null factor law: x − 8 = 0 or x − 2 = 0
  3. x = 8 or x = 2
9.Solve: x2 − 13x + 42 = 0

Answer: x = 6 or x = 7

  1. Factorise: (x − 6)(x − 7) = 0
  2. Null factor law: x − 6 = 0 or x − 7 = 0
  3. x = 6 or x = 7
10.Solve: x2 − 9x + 18 = 0

Answer: x = 3 or x = 6

  1. Factorise: (x − 3)(x − 6) = 0
  2. Null factor law: x − 3 = 0 or x − 6 = 0
  3. x = 3 or x = 6
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