Algebra-1

Question Analysis
This question tests the student's ability to use the explicit formula for a geometric sequence with a negative common ratio.

Key Concept Explanation
The explicit formula for the -th term of a geometric sequence is given by (), where is the first term and is the common ratio. When is negative, the terms alternate in sign.

Step-by-step Solution
1. Identify the first term .
2. Identify the common ratio .
3. Substitute

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