I need help proving this ASAP

Can you simplify 4/7? 24 points will be awarded!

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 .

How do you use the elimination method for this question? explain, because i really want to understand!