The given equation is
Notice that this equation represents a line in slope-intercept form, where its slope is -3.
Now, we have to find a new line parallel to the one above, which means the slope of the new line is also 3 because parallel lines have equal slopes.
Then, we use the given points (-4,6) and the slope -3 to find the equation
Therefore, the equation of the parallel line is y = -3x - 6.