1. The problem statement, all variables and given/known data http://www.sudokupuzzles.net/IMG_0032.gif [Broken] 2. Relevant equations I think I get the basic concept of spans (all possible combinations of vectors with all possible scalers). 3. The attempt at a solution It seems obvious that the span of S would have to be in the span of T, I don't understand what is left to "prove". I have not done a lot of proofs. I don't know where to begin with this problem.