Evaluate .

Answer and explanation

Correct answer: B. 140

  1. Step 1: .
  2. Step 2: .
Answer
140.
Why not the others: 784: that is the sum of cubes. 28: that is the sum of the first powers. 280: the denominator is replaced by .

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Evaluate sum k=1 7 k 2. | EJU Japan Sequences