Answer:
midpoints of segments AB and BD are (-3, 0) and
.
Explanation:
By using number line given in the figure attached,
Coordinates of the extreme ends of the segment are A(-7, 0) and B(-1, 0).
Midpoint of segment AB =

= (-3, 0)
Coordinates of extreme ends of BD are B(-1, 0) and D(6, 0).
Midpoint of segment BD =

=

Therefore, midpoints of segments AB and BD are (-3, 0) and
.