sidebar interaction. Press tab to begin. Read carefully the second bullet point in the slide. Then answer the following question: The RREF of the matrix A = \begin{bmatrix} 1 & 2 & 3 \\ 2 & 4 & 6 \\ 5 & 6 & 7 \end{bmatrix} is U = \begin{bmatrix} 1 & 0 & -1 \\ 0 & 1 & 2 \\ 0 & 0 & 0 \end{bmatrix}. A basis for the row space of A is given by \left\{ \begin{bmatrix} 1 & 2& 3 \end{bmatrix}^T, \begin{bmatrix} 2 & 4& 6 \end{bmatrix}^T ight\}