I really can't see other issues clearly.
This is the last question for you.
18. Solution:
(1)CD is parallel to the X axis, then the ordinate of point C is equal to d, that is, n=5.
(2) If (2)CD is parallel to the Y axis, the abscissa of point C is equal to d, that is, m- 1=3 and m=4.
To sum up, m=4 and n=5.
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