DS: Line goes through (5,a). Is the slope<0?
1) Line goes through (a,5)
2) Line goes throug (20,a)
1)是大于0; 2)是等于0吧?该选哪个呢?作者: cranberry 时间: 2003-1-15 19:14
the slope = a-5/5-a,so if a <5 or a>5,the slope will be negative,but if a=5,then there will be no answer .作者: 猫猫头 时间: 2003-1-15 19:46