答:
平面上三点共线,则三个点两两连线的斜率相等
A(-2,m),B(m,4),C(-3,1-m)三点共线
Kab=Kbc=Kac
(m-4)/(-2-m)=(1-m-4)/(-3-m)
-(m-4)/(m+2)=1
4-m=m+2
2m=2
m=1
答:
平面上三点共线,则三个点两两连线的斜率相等
A(-2,m),B(m,4),C(-3,1-m)三点共线
Kab=Kbc=Kac
(m-4)/(-2-m)=(1-m-4)/(-3-m)
-(m-4)/(m+2)=1
4-m=m+2
2m=2
m=1