Such as (x-1) (x-2) 2 >; 0, find points A (1, 0) and B (2, 0) on the number axis, make a curve, start from the upper right of the number axis, and go down to point B, but you can't pass it. Go back and pass through point A, so its solutions are (1, 2) and (2, positive infinity).

This method is used when even powers are encountered, which is called odd-crossing even cycles.