By 2012,they hope to set up a network of pick-up and drop-off locations for rented bicycles throughout New York City.

VOA: standard.2010.01.31

How far along do I have to go drop off a - c when I have slope -2b?

斜率-2b的线还要经过哪个横坐标呢

耶鲁公开课 - 博弈论课程节选