Hello! I need a bit of help here

Because it doesn’t go on for 15 hours only for 9

The format that this si used in is Y=MX+B. Y means the y cordinant and X means the x cordinant. B is the y intercept, or where the line goes through the y line. In this case B is 2/3. M is the slope. The rise is -5 and the run is 2 in this case. The slope is -5/2.