## Precalculus (6th Edition) Blitzer

The statement is false. The product of two numbers is positive if they have the same signs. This means that the coordinates of a point such as $(-1, -1)$, which is in Quadrant III, also has a positive product. A corrected statement is: If the product of a point's coordinates is positive, the point must either be in Quadrant I or Quadrant III.