Here's the question you clicked on:
sswann222
What is the relationship between the four fundamental subspaces of a matrix?
dimension of column space of A = rank[A] dimension of row space of A = rank[A] dimension of nullspace of A = n - r dimension of nullspace of A^T = m-r
alright now we have to make sure we find the final connection how they Col(A) = Row(A^t)