The formula to find the mid-point of a line segment give the two end points is:
M
=
(
x
1
+
x
2
2
,
y
1
+
y
2
2
)
Where
M
is the midpoint and the given points are:
(
x
1
y
1
)
and
(
x
2
y
2
)
Substituting the values from the points in the problem gives:
M
=
(
−
3
+
1
2
,
3
+
−
3
2
)
M
=
(
−
2
2
,
0
2
)
M
=
(
−
1
,
0
)