| Exam Board | CAIE |
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| Module | P3 (Pure Mathematics 3) |
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| Year | 2015 |
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| Session | June |
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| Topic | Exponential Equations & Modelling |
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2 Using the substitution \(u = 4 ^ { x }\), solve the equation \(4 ^ { x } + 4 ^ { 2 } = 4 ^ { x + 2 }\), giving your answer correct to 3 significant figures.