How do you work out the equation of a parallel line?

To work out the equation of a 2x – 4y = 8 through the point (3,0) take the straight-line equation and simplify to find the value of the gradient(m). 2x – 4y = 8 minus 2x is 4y = -2 + 8, then divide the equation by 4 = y = ½ x – 2. Now subsitie x in the equation for 3 = 0 = ½ x 3 + b which is 0 = 3/2 + b then minus 3/2 to isolate b to get -3/2 = b Put this back into the equation y = ½ x + b which is y = ½ x + 3/2 and the straight line equation though the point (3, 0)