What number must be added to 1575 to result in a sum of 8625

This is geometry. could anyone ? i can't fail this class. my grade is quite low already.

Polygon mnopq is dilated by a scale factor of 0.8 with the origin as the center of dilation, resulting in the image m′n′o′p′q′. the coordinates of point m are (2, 4), and the coordinates of point n are (3, 5). the slope of is .

Which of the following answers is 5/25 simplified? 1/5 5/5 2/5 1/25