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Year 12 Factorising and Solving Quadratics Worksheet — Level 2 — Practice Set 3 — Answers

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Success TutoringWorksheetsAnswer sheetYear 12 · Mathematics · Quadratics

Year 12 Factorising and Solving Quadratics Worksheet — Level 2 — Practice Set 3 — Answers

Factorise, then use the null factor law.

1.Solve: x2 − 4x + 4 = 0

Answer: x = 2 or x = 2

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

Answer: x = 1 or x = −4

  1. Factorise: (x − 1)(x + 4) = 0
  2. Null factor law: x − 1 = 0 or x + 4 = 0
  3. x = 1 or x = −4
4.Solve: x2 + 2x − 15 = 0

Answer: x = −5 or x = 3

  1. Factorise: (x + 5)(x − 3) = 0
  2. Null factor law: x + 5 = 0 or x − 3 = 0
  3. x = −5 or x = 3
5.Solve: x2 − x − 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
6.Solve: x2 + 16x + 64 = 0

Answer: x = −8 or x = −8

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

Answer: x = −7 or x = −6

  1. Factorise: (x + 7)(x + 6) = 0
  2. Null factor law: x + 7 = 0 or x + 6 = 0
  3. x = −7 or x = −6
8.Solve: x2 − 4x − 5 = 0

Answer: x = 5 or x = −1

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

Answer: x = 1 or x = −8

  1. Factorise: (x − 1)(x + 8) = 0
  2. Null factor law: x − 1 = 0 or x + 8 = 0
  3. x = 1 or x = −8
10.Solve: x2 + 4x − 45 = 0

Answer: x = 5 or x = −9

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