Question

Find the sum of the arithmetic sequence. -4, -1, 2, 5, 8, 11, 14

Answer 1

Answer:

35

Step-by-step explanation:

Answer 2

Answer:

  35

Step-by-step explanation:

Since the sequence is so short, you can simply add the terms. It is convenient to do them pairwise, working inward from the first+last:

  (-4+14) +(-1+11) +(2+8) +5

  = 10 +10 +10 +5

  = 35

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Or, you can find the average term as the average of the first and last terms:

  average term = (-4+14)/2 = 5

Then the sum is the product of this and the number of terms:

  sum = (number of terms)×(average term) = 7 × 5 = 35