The equation would be y = -3x + 2. The slope is -3 and the y intercept is 2. I found the slope by using the slope formula:
y2 - y1 2 - 5
-------------- = ------------- = -3
x2 - x1 2 - 1
I found the y intercept by looking at the graph and finding the point where the x and y values are the same.