在同一平面内画5条直线最多可有几个交点,n条呢
问题描述：
在同一平面内画5条直线最多可有几个交点,n条呢
甲车行的路程比乙车多 而乙车用的时间比甲车少 则甲、乙两车速度比为7:10。请判断对错
There are eighty language teachers in a university.Six-two teachers can speak English,and thirty-five teachers can speak French.We can know________ teachers can only speak English.
The perimeter of Rectangle A (长方形A的周长) is 70 meters.If the length (长) is increased (增加) by 10\3 and the width (宽) is reduced (减少)by 2\5,we get Rectangle B.But the perimeter of Rectangle B remains (保持) the same.So the area (面积）of Rectangle A is_________m2.
答
在同一平面内画5条直线最多可有几个交点,n条呢在同一平面内画5条直线最多可有10个交点,n条直线最多可有n(n-1)/2个交点呢甲车行的路程比乙车多 ,而乙车用的时间比甲车少 ,则甲、乙两车速度比为7:10.请判断对错这题可...两个by后面分别为3\10和2\5设长和宽分别为x、y米{2(x+y)=70{2[(1+3/10)x+(1-2/5)y=70解得：x=20,y=1520*15=300(㎡)