Suppose that B is a 12 × 9 matrix with nullity 5. For each of
the following subspaces, tell me their dimension, along with what
value of k is such that the subspace in question is a subspace of R
k . (For example, a possible – though incorrect – answer is that
Col B is a subspace of R 2 .) So, you’ll need eight answers for
this problem (two answers for each of the four parts). • Col...