Looks like u got the slope mixed up with the y intercept. The y intercept is simply where the line touches the y axis which is at 5. The slope is the rise over run of the line. Using the two points on the graph u can see it rises 3 for every 1 it moves horizontally. And since the line is starting higher then it end the slope is negative meaning the final slope is -(3/1), or just -3