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4MA1/2F Jun 2023, Question 15: Substitution

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 2F (Foundation) · Calculator · 4 marks

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The question, in short

Identify the error in Finn's order of operations working for 5 + 3² + 12, insert brackets to make 2 × 6 − 4² − 14 = 10 true, and evaluate x² + 5y at x = −3, y = 2.

Summarised in our own words. Use the official paper for the exact wording and any diagrams.

Part (a) · 1 mark

State what mistake Finn made when evaluating 5 + 3² + 12, referring to the order of operations.

  1. 1Finn did 5 + 3 before squaring, but index comes before addition in order of operations.
  2. 2The correct step is to calculate 3² = 9 first.

AnswerFinn added 5 and 3, but he should have squared the 3 first.

Part (b) · 1 mark

Add one pair of brackets to 2 × 6 − 4² − 14 so the result equals 10.

  1. 1Evaluate inside brackets first: 4² = 16
  2. 216 − 14 = 2
  3. 3Now the expression is 2 × 6 − 2
  4. 42 × 6 = 12
  5. 512 − 2 = 10

Answer2 × 6 − (4² − 14)

Part (c) · 2 marks

Calculate x² + 5y given x = −3 and y = 2.

  1. 1x² = (−3)² = 9
  2. 25y = 5 × 2 = 10
  3. 39 + 10 = 19

Answer19

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