Algebra-1

Question Analysis
This question tests the student's ability to use the explicit formula for the nth term of a geometric sequence with a negative common ratio. The problem provides the first term and the common ratio, and asks for the 4th term.

Key Concept Explanation
The explicit formula for the nth term of a geometric sequence is (). This formula works even when the common ratio is negative, and it is important to handle the sign correctly.

Step-by-step Solution
1. Identify the given values: , , and .
2. Substitute these values into the explicit formula: