Question

[Phạm Thị Khánh Linh]

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2/5x7 + 2/7x9 + 2/9x11 + ... + 2/29x31

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Answer 1

[Lê Thị Mỹ Hằng]

\(=\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\)\(.....+\frac{1}{29}-\frac{1}{31}\)

\(=\frac{1}{5}-\frac{1}{31}\)

  \(=\frac{26}{155}\)

Answer 2

[love karry wang]

bộ bị khùng hay sao mà...