First you have to make out the equation in slope intercept form by subtracting x on both sides, which then equals 2y= -x +12. When you divide by 2, you get y=-1/2+6. The slope is -1/2 and if you wanna find the parallel line, you need to use the same slope. Then using point slope form (y-y1=m(x-x1) you get y-0=-1/2(x-4) when you distribute -1/2 your equation becomes y=-1/2x+2, which would be your parallel line