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The sum of n terms of an arithmetic

sequence is 294. The first term is 8 and
the common difference is 2.
Find the number of terms, n, in the
arithmetic sequence.

User StockB
by
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2 Answers

3 votes

Final answer:

To find the number of terms in the arithmetic sequence, use the sum formula and solve the resulting quadratic equation.

Step-by-step explanation:

To find the number of terms, n, in the arithmetic sequence, we can use the formula for the sum of an arithmetic series:

S = (n/2)(2a + (n-1)d)

Given that the sum of n terms is 294, the first term is 8, and the common difference is 2, we can substitute these values into the formula:

294 = (n/2)(2(8) + (n-1)(2))

Simplifying the equation, we get:

294 = (n/2)(16 + 2n - 2)

294 = (n/2)(14 + 2n)

Multiplying both sides by 2 to eliminate the fraction, we have:

588 = n(14 + 2n)

Expanding the equation and rearranging terms, we get:

2n^2 + 14n - 588 = 0

Now we can solve this quadratic equation for n using factoring or the quadratic formula to find the number of terms in the arithmetic sequence.

User Wyrmwood
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3 votes
Answer: n = 14
Use formula: Sn=n/2(2(u1)+(n-1)(d))
The sum of n terms of an arithmetic sequence is 294. The first term is 8 and the common-example-1
User Jannet
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