First, let's find the slope. Since the line is horizontal, it's slope has to be 0 (this is because slope = rise/run, there is no "rise" in a horizontal line therefore the slope is 0)
Now, we need to find the y-intercept. This is where the line intercepts the y-axis. Looking at the graph, the line intercepts the axis at (0,-4), therefore the y-intercept is -4.
