0580/22 May/Jun 2021, Question 18: Composite Functions
Cambridge IGCSE Mathematics 0580 · Paper 22 (Extended) · Calculator · 4 marks
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The question, in short
Given f(x) = x² − 25 and g(x) = x + 4, solve the equation fg(x + 1) = gf(x).
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Solution · 4 marks
- 1g(x + 1) = x + 5, so fg(x + 1) = (x + 5)² − 25 = x² + 10x
- 2gf(x) = x² − 25 + 4 = x² − 21
- 3x² + 10x = x² − 21
- 410x = −21
- 5x = −2.1
Answer−2.1
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Also searched as: 0580/22/M/J/21 · 0580_s21_qp_22 · 0580 s21 22 · question 18.
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