Answer:
17
Step-by-step explanation:
First label the 2 points.
A = (3, 1/2, 5), B = (3, 1/2, -12)
Then calculate the vector from A to B:
[tex]\vect{AB} = (0, 0, -17)[/tex]
And then calculate it's length by the formula:
[tex]||\vect{a}|| = \sqrt{x^2 + y^2 + z^2}[/tex], where x, y, z are the coordinates related to the vector.
[tex]||\vect{AB}|| = \sqrt{0^2 + 0^2 + (-17)^2} = \sqrt{(-17)^2} = |17| = 17[/tex]
