rr  =
ˆ
ˆ
ˆ
ˆ
ˆ
ˆ
3
4
( 2
3
5
)
i
j
k
i
j
k
+
+
+ λ
−
+ (1)
Let P be the point where the line AB crosses the XY-plane Then the position
vector of the point P is of the form 
yj
xi
ˆ
ˆ + This point must satisfy the equation (1)