If
$$\mathbf{b}_{1}=\left[\begin{array}{r}-2 \\-6 \\3 \\-1 \\-2\end{array}\right] \quad \text { and } \quad \mathbf{b}_{2}=\left[\begin{array}{r}-4 \\-6 \\0 \\0 \\1\end{array}\right]$$
write the matrix $B=\left[\mathbf{b}_{1}, \mathbf{b}_{2}\right],$ and determine the row vectors of $B$.