(1)
y+1=0 (1)
x+2z-7 =0 (2)
from (1) =>y=-1
case 1: x=1
from (2)
1+2z-7 =0
z= 3
A(1,-1,3) 在 直线 y+1=0 ,x+2z-7 =0 上
case 2: x=3
from (2)
3+2z-7 =0
z=2
B(3,-1,2) 在 直线 y+1=0 ,x+2z-7 =0 上
AB =OB-OA=(3,-1,2) -(1,-1,3) = (2,0-1) =直线 y+1=0 ,x+2z-7 =0 的方向向量
过点A(1,-1,3), 方向向量(2,0-1), 直线方程
(x-1)/2 = (z-3)/(-1) and y=-1
(2)
(x-1)/2 = (z-3)/(-1) =t
参考方程
x=2t+1
y=-1
z=-t+3