Question

Determine if b is a linear combination of a1, a2 and a3, the columns of the matrix A.

I put the two together and formed a matrix and reduced it. What do I do from here?

Answer 1

Creating the 3x4 matrix and then swapping rows 2 and 3 we get:

1 0 5 2
0 2 8 6
-2 1 -6 -1

Row 3 + 2x Row 1

gives us

1 0 5 2
0 2 8 6
0 1 4 3

change Row 3 < Row2 - 2x Row 3

gives:

1 0 5 2
0 2 8 6
0 0 0 0

I think this is right, lol I found it off somewhere to explain then I checked