’s and direction ratios of a line are proportional, we have
21
29
x
 =
1
1
3
4
29
29
y
z
=
−
= k
i e ,
x1 =
29
2k , y1 = 
1
3
4
,
29
29
k
k
z
−
=
Fig 11 11
© NCERT
not to be republished
 MATHEMATI CS
482
Substituting these in the equation of the plane, we get k = 
29
6