A cab company offers a special discount on fare to senior citizens. The following expression models the average amount a cab driver of the company collects on a particular day, where x represents the number of senior citizens who travel by the company's cabs.

Every weekday, mr. jones bikes from his home to his job. sometimes he rides along two roads, the long route that is shown by the solid lines. other times, he takes the shortcut shown by the dashed line. how many fewer kilometers does mr. jones bike when he takes the shortcut instead of the long route?