Show that the line through the points `(4, 7, 8), (2, 3, 4)`is parallel to the line through the points `( 1, 2, 1)`,`(1, 2, 5)`.

Explanation

To show that the line through the points \( (4, 7, 8) \) and \( (2, 3, 4) \) is parallel to the line through the points \( (1, 2, 1) \) and \( (1, 2, 5) \), we need to find the direction vectors of both lines and check if they are scalar multiples of each other.

### Step 1: Find the direction vector of line AB

Let point A be \( (4, 7, 8) \) and point B be \( (2, 3, 4) \).

The direction vector \( \vec{AB} \) can be calculated as:
\[
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