6. Suppose the line with equation y = ax + b intersects the graph of y = x3 x at three distinct points A, B, and 0, listed in increasing order of their alecoordinate. Show that if AB = BC, then b = 0. 7. A circle centred at the origin with radius 5 has exactly 12 lattice points on it (A lattice point is a point (53,31) where a: and y are both integers). How many circles of radius 2 pass through exactly two of these lattice points? [Hintz At most, how far apart can two points on a circle of radius 2 be?]