The equation y = 3x and y = 12x <span>represents a proportional relationship. Because i</span>n a proportional relationship, the graph should pass the 0,0 coordinate. It means if you put x=0 to the equation, the result would be y=0. The graph will go in format of y=mx and if we put x = 0 in both equations we get y = 0 and in other two equations if you put x = 0 you will not get y = 0.