Question 1

If I have matrix v1 = (1,-1,2) v2 = (4,-6,7) and v3 (-1,1,k)

Am I right in saying that if k = -2, v1,v2,v3 is linearly dependent, because v3 = -1(v1)?

And following that, if I had to write one vector as a linear combination of the other two, would it be correct to say v1 = 0(v2) - 1(v3)

Question 2

The following matrix is row equivalent to A. Find the general solution to Ax = 0

1 -4 -2 0 3 -5 0 0 1 0 2 -1 0 0 0 0 0 1 0 0 0 0 0 0

I get that the basic variables are x1 and x3, since they are pivots. But is x6 a basic variable or is it free? I'm confused because 1x6 = 0 and 0x6 = 0.