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find the sum of the first 12 terms of the arithmetic sequence 4 11 18 25 32​

Sagot :

Answer:

The answer is 81.

Step-by-step explanation:

The nth term can be found via formula an = a1 + (n-1)d, where a1 is the first term.

The number 7 is known as the common difference.

11-4=7

So, an = 4 + (n-1)(7)

an = 7n - 3

a12 = 7(12) - 3 = 81