The basic equation of a line is I=the general form y = mx + c. Where c is a constant and m is the gradient of the lineFor lines to be parallel they must have the same gradient, then they will never crossThe gradient for line L is therefore 3, as this is the number in front of xBy rearranging the equation of line Q to fit the general form we find that:3y = 9x - 5y = 3x - (5/3)Therefore line Q also has the same gradient and is thus parallel