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0580/21 Oct/Nov 2022, Question 20: Difference of Two Squares

Cambridge IGCSE Mathematics 0580 · Paper 21 (Extended) · Calculator · 5 marks

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The question, in short

Factorise two algebraic expressions completely: a four-term expression in x and y, and a cubic expression in x and y.

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

Part (a) · 2 marks

Factorise 1 + x − y − xy completely.

  1. 11 + x − y − xy = (1 + x) − y(1 + x)
  2. 2= (1 + x)(1 − y)

Answer(1 + x)(1 − y)

Part (b) · 3 marks

Factorise 2x³ − 18xy² completely.

  1. 1Common factor 2x: 2x(x² − 9y²)
  2. 2x² − 9y² is a difference of two squares
  3. 3= 2x(x + 3y)(x − 3y)

Answer2x(x + 3y)(x − 3y)

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Also searched as: 0580/21/O/N/22 · 0580_w22_qp_21 · 0580 w22 21 · question 20.
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