Which of the following vectors are parallel?

u=2i+4j-2k, v=i-j+3k
w=-i-2j+k, p=i+j+k
q=4i-4j+12k, r=i-j+k

watch for properties such as scalar multiples.

u = 2[1,2,-1] and q = 4[1,-1,3] and w = -1[1,2,-1]

now it should be easy to decide, I see some