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4MA1/2H Jan 2019, Question 12: Rearranging Formulas

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 2H (Higher) · Calculator · 9 marks

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The question, in short

Simplify two expressions, factorise a quadratic expression fully, and rearrange a formula to make r the subject.

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

Part (a) · 1 mark

Simplify n to the power zero.

  1. 1Anything (except 0) to the power 0 is 1, so n⁰ = 1

Answer1

Part (b) · 2 marks

Simplify the cube of 3x²y⁵.

  1. 1Cube each part: 3³ × (x²)³ × (y⁵)³
  2. 23³ = 27, (x²)³ = x⁶, (y⁵)³ = y¹⁵
  3. 3= 27x⁶y¹⁵

Answer27x⁶y¹⁵

Part (c) · 2 marks

Factorise 2e² − 18 completely.

  1. 12e² − 18 = 2(e² − 9)
  2. 2e² − 9 = (e − 3)(e + 3)
  3. 32(e − 3)(e + 3)

Answer2(e − 3)(e + 3)

Part (d) · 4 marks

Rearrange m = √((6a + r)/(5r)) to make r the subject.

  1. 1Square both sides: m² = (6a + r)/(5r)
  2. 2Multiply both sides by 5r: 5rm² = 6a + r
  3. 3Collect the r terms: 5rm² − r = 6a
  4. 4Factorise: r(5m² − 1) = 6a
  5. 5Divide: r = 6a / (5m² − 1)

Answerr = 6a / (5m² − 1)

Stuck on a step? Read the free lesson: Rearranging Formulas

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