Question

已知p1(-3,2,),p2(9,4),延长p1p2至p,使p1p/pp2=-3,则点p的坐标为(请写过程)

Answer 1

设p(x,y)

则p1p=(x+3,y-2),pp2=(9-x,4-y)

因为p1p/pp1=-3

所以(x+3)/(9-x)=-3,(y-2)/(4-y)=-3

解得x=15,y=5,p(15,5)