设AB两地距离为x甲乙速度分别为a,b(甲从A到B,乙从B到A )65/a=(x-65)/b (2x-35)/a=(x+35)/b 一式化为a=65b/(x-65),带入二式(2x-35)/[65b/(x-65)]=(x+35)/b 2xb-35b=(x+35)[65b/(x-65)] 2x^2b-35bx-130bx+2275b=65bx+2275b2x^b=230bxx^2=135xx1=0(不符题意,舍去_x2=135km