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    OlympiadMediumAlgebra7–9

    What is the sum of all the coefficients in the expansion of (2x−1)5(2x - 1)^{5}?

    Qual é a soma de todos os coeficientes do desenvolvimento de (2x−1)5(2x - 1)^{5}?

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    Solution

    Substituting x=1x = 1 adds every coefficient at once: (2×1−1)5=15=1(2 \times 1 - 1)^{5} = 1^{5} = 1. Expanding term by term is unnecessary.