2. If the null space of a 5x6 matrix has dimension = 4, what is the dimension of the row space of A?
3. If A is a 4x3 matrix, what is the largest possible dimension of the row space of A?
4. If A is a 3x4 matrix, what is the largest possible dimension of the row space of A?
5. If A is a 2x5 matrix, explain why it is impossible that dim Nul(A) ≤ 2.