Proportional? I think that is the answer.
The slope intercept form of the equation of a line is given as:
y = mx + c
where m = the slope of the line
c = the y - intercept of the line
1) Two line are parallel if they have the same slope
That is:

2) Two equations are perpendicular if the slope of one is the negative inverse of the other.

3) Two equations are coincidental if they have the same slope and the same y intercept
You should use 2 cups of chocolate
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The first point is (x1,y1). The second point is (x2,y2)
Since the first point is (-1, -3), we can say (x1, y1) = (-1, -3)
So ,
Since the second point is (-4, -8), we can also say (x2, y2) = (-4, -8)
So ,
Put this all together to get: , , , and </span>