Let $A = \begin{bmatrix}3&3&3\\3&5&1\\-2&4&-8\\-2&-4&0\\4&9&-1\end{bmatrix}$
Give a basis for the column space of A
So what I've done so far is put it in RREF (which was a task itself) and got
$\begin{bmatrix}1&0&2\\0&1&-1\\0&0&0\\0&0&0\\0&0&0\end{bmatrix}$, but I'm not sure what to do next to give the "basis" of the column space of A
Best Answer
The columns corresponding to the pivots of your original matrix will be a basis for the column space.