show that vectors a=3i-2j-k and b=-6i+4j+2k are paralled

a=3i-2j-k and b=6i+4j+2k.
if they are parallel then a×b=0
(a×b)=(3i -2j -k)×(6i+ 4j +2k)=0
(a×b)=[ i j k ]
[ 3 -2 -1 ]
[ 6 4 2 ]
[ ]
i(-4+4)j(-6+6)k(-12+12)
=0
ie (a×b)=0
ab sin theta=0
as not equal to 0
and
b not equal to 0
sin theta=0 or theta=0
Hence a and b are parallel.since angle between them is 0 degree