Which of the following values could be the y-coordinate of the point (10, _) that is 13 units from (10, 6)?
Both points have the same x-coordinate (10), thus for the first point to be 13 units away from (10, 6), the y-coordinate could be one of these options:
6 + 13 = 19
6 - 13 = -7
This gives us to choose D. -7