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The question in the image asks for the sum of the first 10 terms of an arithmetic sequence, where three of the terms are given: 8, \( x \), and 22. Let's solve this step by step:

### 1. Identify the common difference
In an arithmetic sequence, the difference between consecutive terms is constant. Let's denote this common difference as \( d \).

The terms given are:
- First term \( a_1 = 8 \)
- Third term \( a_3 = 22 \)

We can use the formula for the \( n \)-th term of an arithmetic sequence:
\[
a_n = a_1 + (n - 1) \cdot d
\]

For the third term:
\[
a_3 = a_1 + 2d
\]

Substituting the values:
\[
22 = 8 + 2d
\]
\[
2d = 22 - 8 = 14
\]
\[
d = 7
\]

### 2. Calculate the second term
Now that we know the common difference is 7, we can find the second term \( a_2 \):
\[
a_2 = a_1 + d = 8 + 7 = 15
\]

So, the sequence is:
\[
8, 15, 22, \dots
\]

### 3. Sum of the first 10 terms
The formula for the sum of the first \( n \) terms of an arithmetic sequence is:
\[
S_n = \frac{n}{2} \cdot (a_1 + a_n)
\]

For \( n = 10 \), we need the 10th term \( a_{10} \):
\[
a_{10} = a_1 + (10 - 1) \cdot d = 8 + 9 \cdot 7 = 8 + 63 = 71
\]

Now, calculate the sum:
\[
S_{10} = \frac{10}{2} \cdot (8 + 71) = 5 \cdot 79 = 395
\]

### Final Answer: The sum of the first 10 terms is 395, so the correct choice is **A**.

Would you like more details on any part of the solution?

Here are some related questions to explore further:
1. How do you find the sum of the first \( n \) terms of any arithmetic sequence?
2. What happens if the common difference is negative?
3. Can an arithmetic sequence have non-integer terms?
4. What is the formula for the sum of terms in a geometric sequence?
5. How would you adjust the formula for finding the sum if the sequence starts with a negative number?

**Tip:** Always check that the terms in an arithmetic sequence maintain a constant difference!

Diketahui 8, x - 4, 22, ... adalah barisan aritmetika. Jumlah 10 suku pertama barisan tersebut adalah ....

Learn how to calculate the sum of the first 10 terms of an arithmetic sequence given the terms 8, x - 4, and 22. This detailed solution includes the formula for the nth term and the sum of the sequence. Suitable for students in Grades 9-12.

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