This is a really odd question to me. Usually we talk about b (in Ax=b) spanning the columns of A but here its talking about x spanning A. If x=<-3,4,8> (this is a vertical 3x1 matrix) is a solution to Ax=0, then is x in the set spanned by the columns of A? I'm pretty sure it is no, but i can't explain why? (briefly). And i don't know how to change the statement so it would be true.