Input 1[XYZ ]

Input 2[XYZ ]

These two vectors get mixed.

Mix Amount[XYZ ]

Returns Input 1 linearly interpolated to Input 2 by Mix. When Mix is 0.0, Input 1 will be returned. When Mix is 1.0, Input 2 will be returned.

So the used formula is: Out = Input 1 + (Input 2 - Input 1) * Mix Amount, with Mix Amout being a value between 0.0 and 1.0.