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0580/42 Feb/Mar 2025, Question 18: Expand and Simplify

Cambridge IGCSE Mathematics 0580 · Paper 42 (Extended) · Calculator · 5 marks

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The question, in short

Factorise the expression 18a² − 98, then expand and simplify the product (x + 4)(2x − 1)(x − 2).

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

Part (a) · 2 marks

Factorise 18a² − 98 fully.

  1. 118a² − 98 = 2(9a² − 49)
  2. 29a² − 49 = (3a)² − 7² = (3a − 7)(3a + 7)
  3. 3= 2(3a − 7)(3a + 7)

Answer2(3a − 7)(3a + 7)

Part (b) · 3 marks

Expand and simplify (x + 4)(2x − 1)(x − 2).

  1. 1(x + 4)(2x − 1) = 2x² − x + 8x − 4 = 2x² + 7x − 4
  2. 2(2x² + 7x − 4)(x − 2) = 2x³ − 4x² + 7x² − 14x − 4x + 8
  3. 3= 2x³ + 3x² − 18x + 8

Answer2x³ + 3x² − 18x + 8

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Also searched as: 0580/42/F/M/25 · 0580_m25_qp_42 · 0580 m25 42 · question 18.
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