Find the equation of the set of points which are equidistant from the points `(1, 2, 3)`and `(3, 2, 1)`.

Explanation

To find the equation of the set of points that are equidistant from the points \( A(1, 2, 3) \) and \( B(3, 2, 1) \), we can follow these steps:

### Step 1: Define the points and the variable point
Let \( P(x, y, z) \) be any point in space that is equidistant from points \( A(1, 2, 3) \) and \( B(3, 2, 1) \).

### Step 2: Set up the distance equations
The distance from point \( P \) to point \( A \) is given by the distance formula:
\[
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