The first two terms of a geometric progression add up to 12. The sum of the third and the fourth terms is 48. If the terms of the geometric progression are alternately positive and negative, then the first term is

Explanation

To solve the problem step by step, we will define the terms of the geometric progression (GP) and set up equations based on the information given.

### Step 1: Define the terms of the GP
Let the first term of the geometric progression be \( A \) and the common ratio be \( R \). The terms of the GP can be expressed as:
- First term: \( A \)
- Second term: \( AR \)
- Third term: \( AR^2 \)
- Fourth term: \( AR^3 \)
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