Slope intercept form, y=mx+b, means that the line y, is represented by a slop m, and a y intercept b. So y=4x means that it has a slope of 4 and goes through the origin, since there is no y intercept. To graph, you would place a point on (0,0) and move over one unit, up 4 (because slope is represented by the rise/run) :)