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Explanation:
The x coordinate of point C is x = 7
The x coordinate of point D is x = -1
Add up these x coordinates to get 7+(-1) = 6
Then cut that result in half: 6/2 = 3
The x coordinate of the midpoint is 3
The y coordinate of the midpoint is found in a similar fashion. You should find the midpoint is located at (3, -3.5) which is the same as saying (3, -7/2) since -7/2 = -3.5
