Suppose that v1,v2,v3 are linearly independent vectors in R^5 and consider the vectors a1,a2,a3 defined by a1=v1+v2-2v3, a2=3v1+v2+4va, and a3=v1+2v2-7v3. Show that at least one of the vectors v1,v2,v3 is not in the span of the vectors a1,a2,a3. I am kind of confused. Should I somehow reduce row echelon it? But how would I even set that up given this type of format? Thank you!