The y intercept is the point where the line intersects the y axis. As we can see the line is intecepting the y axis at point 0,4 or just 4. To find the slope from that point you need to go y places up or down and x places left or right-additionally the point has to be on that line. For example from point 0,4 which is our y-intercept if we go up 1 and over 3 to the right from that point then we get another point that's on the line.
