Question 312331
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*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \sum_{k\,=\,0}^n\ 3\ +\ 9k]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \sum_{k\,=\,0}^n\ 2^k5^{4-k}]




John
*[tex \LARGE e^{i\pi} + 1 = 0]
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