4024/12 May/Jun 2020, Question 22: Functions as a Mapping
Cambridge O Level Mathematics 4024 · Paper 12 (Non-calculator) · Non-calculator · 5 marks
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The question, in short
Given f(x) = 4(3 − x) and g(x) = (5(3x − 2))/x, find the inverse of f and solve g(x) = 6.
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Part (a) · 2 marks
Find f⁻¹(x), the inverse function of f(x) = 4(3 − x).
- 1y = 4(3 − x)
- 2y/4 = 3 − x
- 3x = 3 − y/4 = (12 − y)/4
- 4f⁻¹(x) = (12 − x)/4
Answer(12 − x)/4 or 3 − x/4
Part (b) · 3 marks
Solve the equation g(x) = 6 where g(x) = (5(3x − 2))/x.
- 15(3x − 2)/x = 6
- 25(3x − 2) = 6x
- 315x − 10 = 6x
- 49x = 10
- 5x = 10/9
Answer10/9
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Also searched as: 4024/12/M/J/20 · 4024_s20_qp_12 · 4024 s20 12 · question 22.
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