Parametric equations of the lines are 
and
.
Standard form of parametric equations of the line are
, where vector
is parallel line to the line.
Compare
with standard form.
Parallel line corresponding to the line
is
.
Consider
.
Similarly parallel line corresponding to the line
is
.
Consider
.
If these two parallel lines
are parallel, then the lines
and
also parallel.
The cross product of the two parallel lines is zero.
\Find the cross product of
and
.

Since the cross product is equal to zero, the two lines are parallel. \ \
\The lines
and
are parallel lines.
The lines
and
are parallel lines.