A system of equation has one solution if the slope isn't the same.
In y = -8x -6 and y = -8x + 6, since the slope is the same, it doesn't have one solution.
In y = -8x - 6 and y = -4x - 3, since the slopes aren't the same, we know that this is the answer. But, the thir one also has slopes that are different, meaning that the answer is two and three.
