When there is a parallel line, it means that the slopes are the same but the y-intercepts are different. Since you already have the coordinate with x and y and the slope, all you need to find is such y-intercept. So, you would use point-slope form aka y - y1 = m(x - x1). Replace y1 with 6 and x1 with 4 since in (4, 6), x=4 and y=6, and replace m with -2 since its the slope. Now all you have to do is solve it out and you get the result y = -2x +14.
