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0580/22 May/Jun 2024, Question 21: Simultaneous Equations by Elimination

Cambridge IGCSE Mathematics 0580 · Paper 22 (Extended) · Calculator · 5 marks

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The question, in short

Solve the simultaneous equations 4y + 3x = 13 and y = x² − 18, showing all working.

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

Solution · 5 marks

  1. 1Substitute y = x² − 18: 4(x² − 18) + 3x = 13
  2. 24x² + 3x − 85 = 0
  3. 3(4x − 17)(x + 5) = 0
  4. 4x = −5: y = 25 − 18 = 7
  5. 5x = 17/4: y = 289/16 − 18 = 1/16
  6. 6x = −5, y = 7 or x = 17/4, y = 1/16

Answerx = −5, y = 7 or x = 17/4, y = 1/16

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Also searched as: 0580/22/M/J/24 · 0580_s24_qp_22 · 0580 s24 22 · question 21.
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