Find `| -> x|`, if for a unit vector ` -> a ,( -> x- -> a)dot( -> x+ -> a)=12`.

Explanation

To solve the problem, we need to find the magnitude of the vector \( \vec{x} \) given the equation:

\[ (\vec{x} - \vec{a}) \cdot (\vec{x} + \vec{a}) = 12 \]

where \( \vec{a} \) is a unit vector.

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